149
Scholars' Mine Scholars' Mine Masters Theses Student Theses and Dissertations 1968 Determination of molecular diffusivities in liquids Determination of molecular diffusivities in liquids Pai-Chuan Wu Follow this and additional works at: https://scholarsmine.mst.edu/masters_theses Part of the Chemical Engineering Commons Department: Department: Recommended Citation Recommended Citation Wu, Pai-Chuan, "Determination of molecular diffusivities in liquids" (1968). Masters Theses. 7053. https://scholarsmine.mst.edu/masters_theses/7053 This thesis is brought to you by Scholars' Mine, a service of the Missouri S&T Library and Learning Resources. This work is protected by U. S. Copyright Law. Unauthorized use including reproduction for redistribution requires the permission of the copyright holder. For more information, please contact [email protected].

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Page 1: Determination of molecular diffusivities in liquids

Scholars' Mine Scholars' Mine

Masters Theses Student Theses and Dissertations

1968

Determination of molecular diffusivities in liquids Determination of molecular diffusivities in liquids

Pai-Chuan Wu

Follow this and additional works at: https://scholarsmine.mst.edu/masters_theses

Part of the Chemical Engineering Commons

Department: Department:

Recommended Citation Recommended Citation Wu, Pai-Chuan, "Determination of molecular diffusivities in liquids" (1968). Masters Theses. 7053. https://scholarsmine.mst.edu/masters_theses/7053

This thesis is brought to you by Scholars' Mine, a service of the Missouri S&T Library and Learning Resources. This work is protected by U. S. Copyright Law. Unauthorized use including reproduction for redistribution requires the permission of the copyright holder. For more information, please contact [email protected].

Page 2: Determination of molecular diffusivities in liquids

DETERMINATION OF l'JOLECULAR DIFFUSIVITIES

IN LIQUIDS

BY

PAI-Cl-IUAN \•ru I J9'f .)_

A

TilES IS

submitted to the faculty of the

UNIVERSITY OF MISSOURI-ROLLA

in partial fulfillment of the requirements for the

l'1ASTER OF SCIENCE IN CHBtliCAL ENGINEERING

Rolla, Missouri

1968

Approved by

Page 3: Determination of molecular diffusivities in liquids

ii

ABSTRACT

A porous plate, initially at a uniform solute concentra·tion

is irrunersed in a well-s·tirred pure solvent bath of knm>Jn volume.

I·t is desired to find the molecular diff1;1si vi ty of the solute­

solvent system by observing the change of the solute concentrati9n

in the solvent bath with time. In this study, concentration-time

data were curve-fitted by non-linear, least s~1ares techniques to

the various mathematical solutions describing molecular diffusion

in the porous frit. This technique is used to determine the

diffusion coefficient and predict the value of other parameters

existing in the different mathematical diffusion models. The

results from the different models are critically compared.

The following solute-solvent systems were studied in this

work: ethylene glycol in ethylene glycol; ethylene glycol in

diethylene glycol; ethylene glycol in pr•opylene glycol; cyclo­

hexanol in ethylene glycol; cyclohexanol in diethylene glycol;

and cyclohexanol in propylene glycol at 25, 30, 4-0 and 50°C.

The experime11tal diffusivities determined in this study were

then compared with the values from the proposed prediction equa­

tions of Wilke-Chang, Gainer and Metzner, and Mitchell.

Page 4: Determination of molecular diffusivities in liquids

iii

ACKNOWLEDGEMENT

The author wishes to express his indebtedness to

Dr. Robert M. Wellek, Associate Professor of Chemical Engineering,

who suggested this _study and served as a research advisor. His

help, guidance, kindness, and encouragement are sincerely appreci­

ated.

Page 5: Determination of molecular diffusivities in liquids

iv

TABLE OF CONTENTS

Page

ABSTRACT---------------------------------------------------- ii

ACKNOWLEDGEMENT--------------------------------------------- iii

LIST OF ~FIGURES------------------------------'---------------- vi

LIST OF TABLES-.,--------------------------------------------- vii

PROLOGUE TO THESIS------------------------------------------ x

DETERJ:-.1INATION OF MOLECULAR DIFFUSIVITIES IN LIQUIDS

1. Introduction-------------------------------------------- 1

2. The General Least Squares Technique--------------------- 3

3. ~1athematical Models of Porous Frit Problem-------------- 6

4. Curve-Fitting of Data----------------------------------- 11

5. Discussion and Results----------------------------------- 16

5.1

5.2

5.4

c c. ..; . ....;

Empirical Prediction of Diffusion Coefficients----­

Gainer and Me-tzner Estimation Technique-----------­

Mitchell Estbnation Technique---------------------­

The Rela-tions of Activation Energy of Diffusion and Diffusivity------------------------------------

Conclusion-----------------------------------------

28

30 32

34

39

6. Nome~!clature----- ---------------------------------------- L~l

7. Bibliography-------------------------------------------- 43 APPENDICES

A. Least Squares Analysis of Mathematical Models------- 44

A.l Linear Equation (3.10)------------------------- 45

A.2 Non-Linear Equation (3.9)---------------------- 47

A.3 Non-Linear Equation (3.7)---------------------- 49

B. Results of Calibration and Other Runs---------------- 57

C. Prediction of Molecular Diffusivities Using Correlation E~1ations------------------------------- 89

C.l Calculation of Molecular Diffusion Coefficien-ts Using Wilke-Chang Correlation------------------ 93

C.2 Calculation of Molecular Diffusion Coefficients Using Nodified Eyring Rate Equation------------ 94

C. 3 Calculation of Molecular Diff•~sion Coefficients Using Free Energy of Activation---------------- 103

C.4 Self-Diffusion Coefficient Calculation for Ethylene Glycol-------------------------------- 105

Page 6: Determination of molecular diffusivities in liquids

v

Page

D. General Discussion----------------------------------- 111

D.l The Effect of Calibrated Effective Mass Transfer Area and Effective Mass Transfer Length on Diffusivities----------------------------------- 112

D.2 Calculate the Eignvalues of -~b = tan b ------ 117 n n E. Nomenclature----------------------------------------- 119

F. Bibliography----------------------------------------- 121

G. Computer Programs------------------------------------ 122

VITA--------------------------------------------------------- 136

Page 7: Determination of molecular diffusivities in liquids

vi

LIST OF FIGURES

FIGURE Page

1. Boundaries of Porous Frit for Long Time Diffusion------ 8

2. Boundaries of Porous Frit for Short Time Diffusion----- 10

3. Experimental Relationship Between Diffusivity and Absolute Temperature (Ethylene Glycol as the Solute in Different Solvents)--------------------------------- 37

4. Experimental Relationship Between Diffusivity and Absolute Temperature (Cyclohexanol as the Solute in Different Solvents)------------------------------------ 38

5. Concentration Versus Square Root of Time (Run 1, Sodium Chloride-Water at 25°C)-------------------------------- 58

6. Concentration Versus Square Root of Time (Run 76, Ethylene Glycol-Ethylene Glycol at l.J-OOC) --------------- 59

7. Average Absolute Percent Deviation of the Predicted Molecular Diffusivities for 2 Systems (Ethylene Glycol as the Solute) from the Experimental Values of Equation (3·. 9) with Weighting Factor Versus f and s .----------- 106

8. Average Absolute Percent Deviation of the Predicted Nolecula.r Diffusivities for 3 Systems (Cyclohexanol as the Solute) from the Experimental Values of Equation (3.9) with Weighting Factor Versus f and~ .----------- 107

9. Graphic Solution of - o{b = tan b ~--:------------------- 118 n n ·

Page 8: Determination of molecular diffusivities in liquids

vii

LIST OF TABLES

Table Page

1 Calibrated Mass Transfer Parameters for the Porous Frit--------------------------------------------------- 18

2 Experimentally Predicted Molecular Diffusivities Using Short Time Equations----------------------------------- 20

3 Experimentally Predicted Molecular Diffusivities Using Long Time Equation with Calibrated Leff---------------- 22

lJ. Experimentally Predicted Molecular Diffusivities Using Long Time Equation with Lact--------------------------- 24-

5 Experimentally Predicted Molecular Diffusivities Using Long Time Equation with Leff a_Parameter--------------- 26

6 Comparison of Experimentally Predicted Molecular Diffusivities with Various Correlation Equations------- 27

7 Experimentally Measured Activation Energy of Diffusion Process from Diffusivities----------------------------- 36

. B.l Results of Calibration Runs (Equation 3.10)------------ 60

B.2 Results of Calibration Runs (Equation 3.9)------------- 61

B.3 Results of Calibration Runs (Equation 3.7)------------- 62

B.lJ. Calibrated Mass Transfer Area-------------------------- 6~

B.S Calibrated Mass Transfer Length------------------------ 65 v

B. 6 Calibrated d.. ( = Vf ) Values--------------------------- 66 s

B.7 Tabulated Parameters Using Short Time Equations for. Ethylene Glycol in Ethylene Glycol--------------------- 67

B.8 Tabulated Parameters Using Short Time Equations for Ethylene Glycol in Diethylene Glycol------------------- 68

B.9 Tabulated Parameters Using Short Time Equations for Ethylene Glycol in Propylene Glycol-------------------- 69

B.lO Tabulated Parameters Using Short Time Eqt1ations for Cyclohexanol in Ethylene Glycol------------------------ 70

B.ll Tabulated Parameters Using Short Time Equations for Cyclohexanol in Diethylene Glycol---------------------- 71

Page 9: Determination of molecular diffusivities in liquids

Table

B.l2

B.l3

B.l4-

B.lS

B.l6

B.l7

B.l8

B.l9

B.20

B.21

B.22

viii

Page

Tabulated Parameters Using Short Time Equations for 72 Cyclohexanol in Propylene Glycol----------------------

Tabulated Parameters Using Long Time Equation with Cali­brated Leff for Ethylene Glycol in Ethylene Glycol---- 73

Tabulated Parameters Using Long Time Equation with Cali­brated Leff for Ethylene Glycol in Diethylene Glycol-- 74-

Tabulated Parameters Using Long Time Equation with Cali­brated Leff for Ethylene Glycol in Propylene Glycol--- 75

Tabulated Parameters Using Long Time Equation with Cali­brated Leff for Cyclohexanol in Ethylene Glycol-------- 76

Tabulated Parameters Using Long Time Equation with Cali­brated Leff for Cyclohexanol in Diethylene Glycol------- 77

Tabulated Parameters Using Long Time Equation with Cali­brated Leff for Cyclohexanol in Propylene Glycol------- 78

Tabulated Parameters Using Long Time Equation with L ff a Variable for Ethylene Glycol in Ethylene Glycol---~-- 79

Tabulated Parameters Using Long Time Equation with L ff a Variable for Ethylene Glycol. in Diethylene Glycol~--- 80

Tabulated Parameters Using Long Time Equation with L ff a Variable for Ethylene Glycol in Propylene Glycol----~- 81

Tabulated Parameters Using Long Time Equation with L ff a Variable for Cyclohexanol in Ethylene Glycol------~- 82

B.23 Tabulated Parameters Using Long Time Equation with L ff a Variable for Cyclohexanol in Diethylene Glycol----~- 83

B.21+ Tabulated Parameters Using Long Time Equation with L ff a Variable for Cyclohexanol in Propylene Glycol-----~- 84-

B.25 85

B. 26 86

B.27 87

·B.28 88

C.l 90

C.2 Heat of Vaporization Data----------------------------- 91

C.3 Free Energy of Activation of Diffusion Process-------- 92

Page 10: Determination of molecular diffusivities in liquids

Table

C. I+

c.s

C.6

C.7

D.l

Predicted Molecular Diffusivities Using Wilke-Chang Correlation Equation--------------------------~--------

Predicted Molecular Diffusivities Using Gainer & Metzner Suggested Equation-----------------------------

Predicted Molecular Diffusivities Using Free Energy of Activation------------------------------------------

Comparison of Self-Diffusion Coefficient of Ethylene Glycol-------------------------------------------------

Calibrated Vf Values for Equation (3.7)----------------

ix

Page

95

102

108

110

116

Page 11: Determination of molecular diffusivities in liquids

PROLOGUE TO THESIS

The purpose of this study is to curve-fit concentration ver­

sus time data obtained in a previous study(l2)by various least

X

squares techniques in order to determine the molecular diffusivity

of several binary, liquid-liquid systems. The systems studied

(solute given first) are as follows: ethylene glycol-ethylene

glycol, ethylene glycol-diethylene glycol, ethylene glycol-

propylene glycol, cyclohexanol-ethylene glycol, cyclohexanol-

diethylene glycol, and cyclohexanol-propylene glycol. The

concentration data were measured in this laboratory(l2)using an

unsteady state porous frit technique.

There are two short time and one long diffusion tjme mathe-

rnatical diffusion models derived with different boundary conditions

to describe the porous frit problem. These equations relate to

time and solute concentration of solute to system parameters in a

well mixed solvent bath. The parameters are molecular diffusi-

vity,effective mass transfer area, effective mass transfer length,

volume of the solvent bath and/or bath solute concentration at

time equal zero.

Curve-fitting by the method of least squares is a means of

determining values of the curve-fitting parameters which exist in

the analytical expressions so that the sum of the squares of the

deviations of predicted values from observed values, which we will

call S, is a minimum. This can be done by differentiating S

partially with respect to parameters; the equations so obtained

are equated to zero and solved simultaneously for the parameters.

Page 12: Determination of molecular diffusivities in liquids

xi

The mathematical model may be linear or non-linear in the

parameters. The non-linear equations require iterative techniques~

in which it is necessary to linearize the non-linear equation by

Taylor's series expansions.

The application of these linear and non-linear least squares

techniques and the development of a series of computer programs

to obtain the diffusion coefficients of highly viscous solute­

solvent systems using the short and long time models constitutes

the main contribution of this thesis. The results of the least

squares analyses of the data may lead to differing values of the

diffusion coefficient depending on the model which is used. Thus,

one of the primary goals of this work is to critically analyze the

results obtained from the various models and judge which results

are to be recommended for use.

In the previous study(l2), the use of the long diffusion time

model was not successful. In this work, the least squares analysis

of the long diffusion time model is to be further analyzed, thus

allowing more data to be utilizedo Also~ the short time models

used in the previous study will be analyzed again with several

modifications in the least squares analysis to verify and improve

the results of previous studies.

The values of the molecular diffusi vi ty obtained from the

analyses of the ex.perimental data will then be compared with

several theoretical and semi-empirical methods of predicting

liquid binary diffusivities from the physical properties of the

solute-solvent system.

Page 13: Determination of molecular diffusivities in liquids

xii

The complete derivation of the mathematical models, experi-

mental data, and all details concerning the experimental techniques

used to obtain the data are presented elsewhere(12).

Page 14: Determination of molecular diffusivities in liquids

DETERMINATION OF MOLECULAR DIFFUSIVITIES IN LIQUIDS

Pai-Chuan Wu and Robert I-1. Wellek University of Missouri-Rolla, Rolla, Missouri

1. Introduction

In almost every branch of chemical engineering, there occur

1

~roblems of diffusion and mass transfer in applied kinetics, where

the rate of chemical. reaction is frequently controlled by the

diffusion of a reactant through a fluid layer outside or within

a catalyst pellet; in mixing and blending, where uniformity of

product distribution may depend upon molecular or turbulent mass

transfer; in applied electrochemistry, where diffusion may be the

limiting factor in corrosion or electroplating processes; and

above all, in the separation processes (absorption, adsorption,

distillation, extraction and ion exchange), where diffusion and

interphase mass transfer play key roles(llJ.).

Since no completely adequate theory for the prediction of

binary molecular diffusion coefficients in liquids exists, ex.peri-

mental measurements of the diffusivity are often required. This

is especially true for highly viscous liquid systems where very

little experimental data are available. In all highly viscous

liquids the rates of molecular diffusion are generally considered

to be very slow. This slow rate of mass transfer usually requires

a study of the unsteady state period of mass transfer to determine

liquid molecular diffusivities.

In this work, the concentration data from an unsteady state

porous frit technique for determining the molecular diffusivities

Page 15: Determination of molecular diffusivities in liquids

2

of a solute through high viscosity solvents were curve-fitted by

least squares methods to determine the diffusivity, DAB. A frit

soaked with a solution of solute A in solvent B (initial concen-

tration of A equal to C ) is immersed in a well-agitated bath of 0

nearly pure B. The solute A diffuses through the stagnant solvent

in the interstices of the porous frit by molecular diffusion and

then into the bath; and the concentration of the solute in the

bath (Cf) increases with time (t).

There are two short time models and a long time mathematical

model(l2)relating Cf and t to the system parameters (mass transfer

area, AT; molecular diffusivity, DAB; volume of bath, Vf; initial

solute concentration in solvent bath, Cf0 ; or effective mass

transfer length, L). The models are represented by Equations

(1.1) , (1. 2) , and (1. 3) as follows:

cf - cfo =

4A.r j DAB t (l.la) c - c [ffVf o fo

or

cf :=. 4AT C0 JDAB t +

[IT vf cfo (l.lb)

c 2 2AT DABt

J cf -

= Gxp 4~ ~ABt) [l 0 - erf (1.2) c - c vf fo 0 vf

2 c - c

[ oO -DABb t] f 0 1- _1 __ 2: 2cl. (1.3) = exp n

c -c l+t:X n=ll+ o<+ot2b 2 L2 fo o n

* The term C 0

usually Cf ~ C • is a common approximation for (C - C.c ) , since All nomenclature is defined in tRe No~~nclature

t . 0 0 sec lon.

*

Page 16: Determination of molecular diffusivities in liquids

where

b are the non-zero roots of -d.. b = tan b n n n

and

These three analytical expressions were derived using three

different sets of boundary conditions--with each set leading to

basic equations of varying degrees of validity, usefulness, and

simplicity. These models will be described in more detail in

Section 3.

Vfuen using Equation (1. 2) or (1. 3) to determine DAB, a non­

linear least squares technique should be used. The technique

requires a Taylorts series expansion of the function in terms of

3

the curve-fitting parameters. The resulting equ.ations are linear

and may be easily handled with an iteration procedure. This non-

linear, least squares problem will be described in Section 2.

2. The General Least Squares Technique

The general least squares problem for fitting analytical

expressions to experimental data is to choose the "bestn values of

the parameters in the analytical expessions which makes the sum of

the squares of the deviations a minimum.

Suppose we have the following general analytical form:

(2.1)

Page 17: Determination of molecular diffusivities in liquids

where ,... Y = predicted value of the dependent variable

x. = independent variables (i = 1, 2, ---n) l

a. =parameters (j = 1, 2, ---m) J

4

The best curve-fit of the data is the curve which makes the sum of

"" squares of deviations of the experimental Y from predicted Y values

a mininrum for all N observations. We will call the swn of squares

of deviation S. Therefore, we have the expression:

N A 2 2. (Y.- Y.)

i = 1 l l s = (2. 2)

It is suggested(ll)that a weighted least-squares techniques be

used for situations where the accuracy of the data is related to

the range of the variables. This leads to the following relation:

N 2. A 2

W. (Y. - Y .) i = 1 l l l

s = (2. 3)

where W is a function of Y and is called the weighting factor.

One common modification of the least squares treatment in such

cases is to weight the measurements by the reciprocal of the

estimated variance of the dependent variables(ll). W. may, thus, l

be defined as

1 w. = l d-2 (Y.)

l

(2. 4)

in which () is standard deviation and (1 2 is the variance, which is

given as

N 2 1 2 A 2

(2. 5) (J' = (Y. - y .) N-m i = 1

l l

in which m is the number of parameters.

Page 18: Determination of molecular diffusivities in liquids

The sum of squares, S, will have its smallest value when

__£.§.__ = 0 oa. J

for all j (j = 1, 2, ---m) (2. 6)

5

The parameters, a. (j = 1, 2, ---m) , can be solved simul·taneously J . (1)

from the above m normal equations given ~y Equation (2.6) •

Equation (2.1) may be linear or non-linear in the parameters.

In the linear case, the exact solution can be obtained by applying

the above technique directly, without linearization and iteration.

Equation (1.1) is linear in the curve-fitting parameters. How-

ever, for a non-linear case, the solution may be obtained after

first linearizing the equation with respect to the curve-fitting

parameters and applying an iterative process.

We may linearize (2.1) by expanding the function cf:> about

a~ (selected starting values in the iteration) by means of a J

Taylor's series expansion(6)of the function in terms of the para-

meters, a. (j = 1, 2, ---m). Hence, one obtains the following J

expression:

m

cp (~i,aJ.) = c/>Cxi,aoJ.) + 2 j = 1

0 (a-a ) . --­J

(2. 7)

assuming that a~ is sufficiently close to the solution so that J

second and higher-order terms can be neglected. Equation (2.7)

may be used in either Equation (1.2) or {1.3). The system para­

meters become the correction terms, Aa. = (a-a 0 ) . , which can be J J

evaluated by applying the linear least squares technique. The

1 f f - 0 new va ues a. a ter irst improvement, namely a. - a. + A a., may J J J J

0 be substitu·ted back into Equation (2. 7) as a. for a second

J

improvement. This iterative procedure may be repeated as either

Page 19: Determination of molecular diffusivities in liquids

the correction terms approach zero or the averag~ absolute per-

centage deviation, AAPD, which is defined as

N

AAPD = 100 2. I N i = 1

reaches a minimum.

/\

y. - Y. ~ ~

Y. ~

3. Mathematical Models of Porous Frit Problem

(2. 8)

A porous frit, (-L(x~L), initially at a uniform solute

concentration C0 is immersed in a volume Vf of well-stirred

solvent bath nearly pure solvent B (see Figure 1). Because of

start-up effects, the initial solute concentration in solvent

bath, Cfo' has to be considered as a curve-fitting parameter. It

is desired to be able to find the diffusion coefficient DAB by

observing the change of solute concentration Cf in solvent bath

with t:ime.

Mass transfer in the solvent inside the flat porous frit may

be described by Fick's second law for molecular diffusion(3).

ac --= D ~t

(3.1)

since the edges of the plate are sealed to prevent diffusion in

the y and z directions and the solvent is essentially stagnant

inside the pores of the frit.

6

The mass transfer mechanism outside the surface of the plate,

i.e., in the solvent bath, may be obtained by making a solute

material balance at the interface ben'een the fri·t and the bath.

Page 20: Determination of molecular diffusivities in liquids

7

vf dcf = _ 20 A._ accL,t) dt AB---r ax

(3. 2)

in which A.r is the effective mass transfer area of the plate.

Equation (3.2) assumes the solvent in the bath is perfectly mixed.

Equations(3.1) and (3.2)· may be stated in dimensionless

variables by using the following relations(2):

* c - c dimensionless solute

c = 0 concentration inside c - cfo the plate 0

* c - c dimensionless solute

cf = c 0 f concentration in the - c solvent bath 0 fo

? dimensionless distance

=·..2$;_ from the center of the L plate

dimensionless time

Hence Equations (3.1) and (3. 2) become

where ·

-1· o{

* ac { o; ~=l

(3.3a)

(3. 3b)

(3. 3c)

(3. 3d)

(3.4)

(3.5)

Vf and Vs = volume of the solvent in the solvent bath and

plate, respectively.

Page 21: Determination of molecular diffusivities in liquids

8

* C is a function of ? and~ ; however, since the solvent bath

* is well-agitated, cf is a function of~ alone.

The_solution of Equations (3.4) and (3.5) for long diffusion

time requires the following boundary conditions:

C(x,O) = C 0

ac co, t) = 0 ax

initial concentration profile inside the plate

concentration on the surface of the plate

concentration relation at the center of the plate

initial concentration of the fluid outside the plate

(3. 6a)

(3.6b)

(3. 6c)

(3 .. 6d)

These boundary conditions may be stated in dimensionless form:

x=L x=o

Fig. 1. Boundaries of porous frit for long time diffusion

c* c~ ~o) = o (3. 6e)

(3. 6f)

* ac co, Z) = 0 0~

(3. 6g)

(3. 6h)

The solution of Equations (3.4), (3.5) and (3.6) can be

determined by means of Laplace Transforms as:

Page 22: Determination of molecular diffusivities in liquids

or

where

l-(_!_­~1+0(

00 2o(

~ 2 2 n=l l+cX. +d... b

n

exp -Db 2

t J (--!}_) L2

b are the non-zero roots of: - O(b = tan b n n n

L is the effective mass transfer length from the

center of the frit to the surface.

Equation (3.7) is the same as derived by Mitchell(l2).

9

(3. 7 a)

(3. 7b)

although he presented the solution in the following rearranged

form:

1 l+o(

00 2<X ::E. n=ll+o(+o<2b 2

n

-Db 2t C n ) exp L2

Theoretically, Equations (3. 7) and (3. 8) can be used for the

(3. 8)

calculation of the concentration of solute in solvent bath from

very short time to time approaching infinite. It should be noted

that the term L must be considered as Leff because of the tortuous

nature of the frit pores.

Mitchell(l2)also used other sets of boundary conditions to

other solutions for shor·t time periods. The two short time models

used are summarized as follows (refer to Fig. 2) :

Page 23: Determination of molecular diffusivities in liquids

x=o x=o

x=oo

Fig. 2. Boundaries of porous frit for short time diffusion

10

1st Model:

a. Initial conditions inside and

outside the plate are

C (x,o) = C 0

(3. 8a)

(3. 8b)

b. Since the diffusion t~ne is

assumed short, the solute concen-

tration in the center of the plate

is assumed to remain at the initial

solute concentration

c ( 00' t) = c 0

(3.8c)

c. If there is no resistance to

diffusion outside the plate (x=O)

and the solvent bath is perfectly

mixed.

c co,t) = cf (t) (3.8d)

The solution to Equations (3.1) and (3.2) with these boundary

conditions is

(3.9)

2ndModel: Again for very short time periods, Hollader and

Barker(9)and Mitchell(l2)have derived a model based upon the

assumption that Equations (3.8a-c) are applicable, but the

Page 24: Determination of molecular diffusivities in liquids

11

additional assumption is made that the build-up of solute in the

fluid is negligible. Thus, Equation (3.8d) is replaced by

C (O,t) = Cfo (3.8e)

The solution is

(3.10)

Mitchell(l2)reported that these two short time equations

must be used for diffusion times less than or equal to 0.3 L2/D.

However, in curve-fitting the concentration versus time data to

these short time equations, only the data in the linear range of

concentration versus squai·e root of time were used in the curve-

fitting analyses. This is an even more conservative criterion.

It should be noted that A.r represents an effective area of the

pore openings.

In this work, the curve-fitting of data to Equations (3.7)and

(3.9) are performed using the non-linear least-squares procedure.

The linear least squares data analysis is applied to Equation

(3 .10).

4. Curve-Fitting of Data

The techniques described in Section 2 were used in the least-

squares analysis. Before determining unknown molecular

diffusivities, it is necessary to calibrate the frits through

the use of a solute-solvent system with a known diffusivity.

Page 25: Determination of molecular diffusivities in liquids

12

Case I. Very Short Time Equation (3.10)

Equation (3.10) is a nlinear11 equation; concentration data in ;!,;. .

this ·time period (when plotted versus t 2) can be fitted by the

least-squares technique to a straight line. This equation may be

_used to solve for the parameters Cfo and ~ (or DAB), where Ar is

·unknown for the calibration runs and DAB is un1<nown for other

runs (see Appendix A.l). The parameters determined using Equation

(3.10) are used as the initial values in analysis of Equation (3.9).

Equation (3.10) is considered an ''estimatedn equation. Because of

the approximate nature of boundary condition (3.8e) and because

the results of this model were used only as initial estimates for

the model based upon Equation (3.9), no correction for volume

change of the solvent bath was considered necessary. Therefore,

the initial value of Vf. (equal to 300.0. ml) was used as a constant

in the analysis with Equation (3.10).

In the least-squares technique, either E~1ation (2.2) or

(2.3) for minimizing S may be used. The experimental measurements

of the dependent variable are the counts per minute of the radio-

active solute tracer, in the solvent bath, which is proportional

to the total concentration of the solute in the bath. The standard

deviation may be considered as

(4-.1)

assuming no error in the scintillation counter and all error

related to normal randomness of radioactive decay processes. K1

is a constant which, as a result of algebraic manipulations, is

Page 26: Determination of molecular diffusivities in liquids

13

not used in least-squares analysis. Thus, Equation (2.4) used in

this work is the following form:

(4-. 2)

Both Equations (2 .-2) and (2. 3) ·for minimizing S were tested in this

work for calibration runs based on Equation (3.10).

For a total 19 runs, the average values of AAPD for the un-

weighted and weighted least-squares approach (i.e., Equation (2.2)

and (2. 3)) are 5. 68% and 4. 09% , respectively (see Appendix B, Table

B.l). In effect, the weighting factor gives less weight to the

shorter time data.

The results of curve-fitting of Equation (3.10) for all runs

are included in Section 5 and in more de·tail in Appendix B.

Case II. Short .Iime Equation (3. 9)

Equation (3.9) is an equation which is non-linear in the

parameters, so an iterative-linearization, non-linear least-squares

method based upon Equations (2. 7) , (2. 2) and (2. 3) are to be used •.

The parameters are Cfo and AT (or DAB). The initial values of

these parameters for the iterative process are obtained from

Case I (see Appendix A.2).

Since Equation (3.9) is considered as an exact equation for

the short contact time model, the correction for volume change of

the bath should be performed. It is suggested by Mitchell(l2)

that the average of the initial and final volL@e of the solvent

in the bath be used with Equation (3.9). Thus,

Page 27: Determination of molecular diffusivities in liquids

14-

where

300.0 ml = initial fluid volume in the solvent bath

1.00 ml - volume drawn for every measurement of concentra­

tion

N = total number of data points considered

The total change in V f during an experimental run is usually

quite small since .for the short time models, the total number of

data points considered is about ten.

For minimizing S using the iterative procedure, both Equations

(2.2) and (2.3) are used in ·this study for curve-fitting of the

non-linear Equation (3.9). For a total 19 calibration runs, the

average values of AAPD for Equations(2.2) and (2.3) are 5.65%

and ~.59%, respectively. The molecular diffusivities determined

for the six highly viscous solute-solvent systems using ·the

weighting factor (i.e., using Equation (2.3)) are about 3.85%

greater than those calcUlated without weighting factor (i.e.,

Equation (2.2)). The average value of AAPD for the 49 diffusivity

runs, using Equation (2.3) is decreased 11.7% from the AAPD using

Equation (2.2). The results for each run are included in

Appendix B and discussed in Section 5.

Case III. Long Time Equation (3. 7)

Through the use of Equation (3.7), the author was able to

include in the analysis all the experimental data, except

obviously erroneous measurements, at short and long times. In

Page 28: Determination of molecular diffusivities in liquids

15

general, for any given run, about 1.5 times the number of data

points used in the analysis of Equation (3.9) were used in this

analysis.

There are three parameters in Equation (3.7), namely, Cfo'

Q\, and DAB (or Leff in calibration runs). In this case, Cfo was

first considered as a known quantity as determined in Case II;

therefore, Equation (3. 7) is reduced to two variables: o<. and DAB

(or Leff).

A three-variable (Cfo, r:J.., and DAB or Leff) search using Equation

(3.7) based upon the non-linear least-squares technique also is

performed in this work. The proper choice of the initial values

of Cfo, d.. , and Dll.B (or Leff) in this three-variable analysis is

very important to insure convergence of the iterative scheme to a

reasonable solution. The results of Case II may be used. The

initial values for the three-variable search may be found from the

two-variable search.

The coefficients, bn' in the infinite series in Equation

(3.7) may be calculated as follows:

(a.) Since

-o{b = tan b ('+.4) n n

one can easily find b (n=l,2,--- oO) by using an n

iteration root-solving method (see Appendix D).

(b.) - o( is the slope of the curve of tan b versus b • The n n

absolute value of the slope assumes a large value because the

difference in the values of Vf and Vs is large (about 25). There­

. fore, we can use the recursion formula

Page 29: Determination of molecular diffusivities in liquids

16

(n = 1~ 2~---) (4.5)

where h1 can be found from iteration (see Appendix D).

The results of these two-variable and three-variable searches

are included in Appendix B and discussed in Section 5 and Appendix

D.l.

5. Discussion and Results

The molecular diffusivities are determined for the highly

viscous solute-solvent systems which have a solvent viscosity

range of 6.77 to 43.36 centipoises (see Table 2 and Table C.l).

For calibration of the frits, the sodium chloride-water sys·tem

with known diffusivity of (1.61 ± 0.01) x 10-S cm2/sec at 25°C(18)

and known initial NaCl concentration C of (1.11 x 10-3) g-mo1e 0

per liter in the pores of the frit was 11sed.

The calibration mass transfer parameters for the porous frits

are shown in Table 1. The effective mass transfer area was

determined by using Equation (3.10) with weighting factor, (3.9)

with weighting factor and (3.9) without weighting factor. Using

these three methods, the total average values of the mass transfer

2 area from the calibrated six frits are 11.02, 10.-97, and 11.02 em ,

respectively. The standard deviation of these average values from

the six specific values for the frits are 0.615, 0.453, and 0.579,

respec·tively (see Table B. 4). The standard deviation for the six

frits varied fr~~ 0.567 to 2.365, 0.570 LO 2.541, and 0.550 to

2.729 using the three methods described above, respectively (see

Table B.4) •. Therefore, the total average values are accepted

in this work rather than using a calibration ~ for each particular

Page 30: Determination of molecular diffusivities in liquids

frit. The value of ~ equal 11.02 and 10.97 were used for the

determination of the molecular diffusivity for the case of not

weighting and weighting the data, respectively.

17

The effective mass transfer length and ~value are determined

by using the long time model-Equations (3.7) and (3.8) with two-

variable and three-variable analyses. Basically, these two

equations are identical. However, for convenience in the non-

linear, least squares analysis, form (3.8) is used in the

two-variable search and form (3. 7) is used in the three-variable

search since Cfo ~ppears only once in Equation (3.7). The

calibration values are listed in Table 1. The total average

values of Leff and~ are·0.531 em (2-variable search) and 0.556 em

(3-variable search), and 25.~0 (2-variable search) and 2~.98 (3-

variable search), respectively. The standard deviation of these

total average values from the six specific values of the frits

are 0.016 and 0.026, and 2.210 and 2.401, respectively (see Tables

B.S and B.6). The standard deviation for the six frits varied

from 0.02~ to 0.094, and 0.920 to 0.094 (in case of Leff) using

two-variable and three-variable search, respectively. In the

case of o(, they are 1.018 to 6.889, and 1.074- to 7.283, respec-

tively (see Tables B.S and B.6). Therefore, the total average

values are accepted in this work.

For the determination of the molecular diffusivities, the

following initial concentrations C are used for each system: .. 0

1) -5 Ethylene glycol in ethylene glycol, C0 = 3.60 x 10

g-mole/li ter.

Page 31: Determination of molecular diffusivities in liquids

Frit

No.

1

2

3

I+

5

6

Table 1

* Calibrated Mass Transfer Parameters for the Porous Frit

No. of a Transfer Area· Transfer Length b c d...

Runs A.r" em 2

Leff' em

(3 .10) (3. 9) (3 0 9) (3.8) (3. 7) (3. 8) (3. 7) w w

4 10.88 10.91+ 10.91 0.553 0.569 25.08 24-.22

3 11.52 11.21+ 11.24- 0.557 0.588 23.76 23.08

3 11.73 11.92 11.1+2 0.540 0.569 22.40 22.00

3 10.14 10.44 10.28 0.510 0.517 28.10 27.97

3 10.53 10.35 10.58 0.522 0.536 27.80 27.60

3 11.32 11.22 11.38 0.524- 0.557 25.20 24.99

Avg. 11.02 11.02 10.97 0.531 0.556 25.40 24.98

* Standard deviations of each frit from its particular runs and total average value from six frits see Tables B.4, B.5, and B.6 in Appendix B.

18

aMass transfer area were determined by using short time Equa­tions (3.10) and (3.9) with weighting factor (with 11W11 ) and without weighting factor.

b Mass transfer length were determined by using long time Equa-tion. (3. 7}. Form (3. 8) is in 2-variable search and (3. 7) in 3-variable search.

c~ is a curve-fitting parameter and is defined as the volume ratio of solvent in the bath to solvent in the frit.

Page 32: Determination of molecular diffusivities in liquids

2) Ethylene glycol in diethylene glycol or propylene

glycol, c = ~.so x 10-2 g-mole/liter. 0

3) Cyclohexanol in ethylene glycol, diethylene glycol

-2 or propylene glycol C = 2.~1 x 10 g-mole/liter. 0

The molecular diffusivities determined in this study by

using short time Equations (3.10) and (3.9) with and without

weighting factor, and long time Equation (3.7) with 2-variable

19

and 3-variable search are shown in Tables 2, 3, and ~'respectively.

Since the molecular diffusivi·ties at different temperatures were

determined by at least b.vo runs, the calculated 95% confidence

ranges are also included. The product of 1.96 and the calculated

standard deviation of the diffusivity for a particular run from

the mean value of the diffusivity is the 95% confidence range.

The results for individual calibration and diffusivity runs are

presented in Appendix B. These results include the values of

effective mass transfer area, the effective mass transfer length,

·the initial. solute concentration in sol vent bath, and the absolute

average percentage deviation of the experimentally measured con-

centration from the concentration predicted by Equations (3.10),

(3. 9) and (3. 7) •

The calibrated effective mass transfer area AT and effective

mass transfer length Leff will be directly used as characteristics

of the frit in the molecular diffusivity runs. From the definition

of ~ (= effective volume ratio of solvent bath to solvent in the

frit), the relation of Leff andct to Vf may be checked roughly

with the equation

Page 33: Determination of molecular diffusivities in liquids

20

Table 2

Experimentally Predicted Molecular Diffusivities

Solute

A

Solvent

B

ethylene ethylene glycol glycol

ethylene diethylene glycol glycol

ethylene propylene glycol glycol

cyclo­hexanol

cyclo­hexanol

cyclo­hexanol

ethylene glycol

diethylene glycol

propylene glycol

Us·ing Short Time Equations

25.0 30.0 4-0.0 50.0

25.0 30.0 40.0

25.0 30.0 40.0

.50.0

26.6 30.0 q.o.o 26.6 30.0 4-0.0

26.6 30.0 4-0.0

fJ.B cp

a 95% b

confidence range

(3 .10) (3. 9) (3. 9) (3 .10) (3. 9) (3 .• 9) w w

16.60 1.151 1.040 1.131 13.56 1.501 1~278 1.330

9.4-1 1.818 1.409 1.516 6.77 2.4-42 2.416 2.4-91

27.16 0.739 0.614 0.664-21.61 0.973 0.720 0.763 14.35 1.175 0.852 0.913

4-3.36 0.686 0.519 0.585 32.62 0.791 0.627 0.64-5 19.56 1.14-6 0.847 0.902 12.40 1.4-8~ 1.530 1.502

w w

0.02 0.01 0.17 0.24- 0.02 0.03 0.18 0.24- 0.17

0.02 0.07 0.07 0.09 0.01 0.01 0.33 0.22 0.23

0.28 0.04- 0.05 0.06 0.02 0.01 0.02 0.02 0.02 0.00 0.00 0.02

16.60 0.701 0.755 0.749 0.07 13.56 0.960 0.862 0.886 0.02

0.02 0.04 0.02 0.01 0.07 0.11 9.41 1.438 1.272 1.301 0.48

27.16 0.612 0.601 0.616 0.02 21.61 0.792 0.626 0.653 0.13 14-.35 1.230 1.076 1.102 0.03

43.36 0.183 0.180 0.181 32.62 0.480 0.392 0.404 0.05 19.56 0.858 0.692 0.714 0.18

0.0'+ 0.04 0.01 0.01 0.01 0.00

0.01 0.01 0.01 0.01

aFor more detailed information about number of data points used in run, curve-fitted initial solute concentration in solvent bath and their AAPD~ see Appendix B.

b95% confidence range = 1. 96 O'(DAB). N

2 1 """ - 2 Variance (f (DAB) = N-l . L (DAB.- DAB) J = 1 J

Page 34: Determination of molecular diffusivities in liquids

3 = 300 em ) (5.1)

21

That is, the above relation should be satisfied even though r:;l..and

Leff are determined by one method and ~.from another method.

In diffusivity determination runs, Equation (Sol) was not

always satisfied in the manner just described for the calibration

runs. Considering runs 51, 5~, and 95, for example, the values

obtained for~ were ~5, 36, and 5~, respectively. However, these

three o1.. values did not agr'ee with 2~. 30 which is calculated using

Equation (5.1) with the effective mass transfer area and effective

mass transfer length from the calibration runs. It was found that

for these runs the value of DAB determined from Equation (3.7)

deviated considerably from the values obtained using short time

Equation (3.9). For example, consider ethylene glycol diffusing

0 in diethylene glycol at ~0.0 C: the value of DAB determined for

Equation (3.7) with two-variable and three-variable search are

1.972 and 2.313 cm2/sec., respectively. The calculated AAPD of

these two values from the value of DAB obtained by using Equation

(3.9) with weighting factor (which is 0.913 cm2/sec) are 115% and

14-3%, respectively (see Tables 2 and 3). This seems to imply that

the effective mass transfer length determined from the calibration

runs in which the low viscosity NaCl-water system was used, may -- .

not be the same in the high viscosity diffusivity runs. There

are at least two possible reasons why this could happen. First,

the initial soaking of the dry frit with the solute-solvent system

may not have been uniform for all runs. Secondly, the frit will

Page 35: Determination of molecular diffusivities in liquids

Table 3

Experimentally Predicted Molecular Diffusivities

Using Long Time Equation with Calibrated ~ff

Solute

A

Solvent

B

ethylene ethylene glycol glycol

25.0 30.0 40.0* 50.0

16.60 13.56

9.41 6.77

ethylene diethylene 25.0 27.16 glycol glycol 30.0* 21.61 ·

40.0 14.35

ethylene propylene glycol glycol

cyclo­hexanol

ethylene glycol

25.0 30.0 40.0* 50.0

*

43.36 32.62 19.56 12.40

26.6* 16.60 30.0* 13.56 40.0 9. 41

cyclo­hexanol

* diethylene 26.6* 27.16 glyc~l 30.0 21.61

40.0 14.35

cyclo- propylene hexanol glycol

*

* 26.6* 43.36 30.0* 32.62 40.0 19.56

6 DAB x. 10

2 em /sec (3. 8) (3. 7)

1~108 1.184 1.720 4.138

0.847 1.001 1.972

0.674 0.695 1.255 3.124

2.462 1.757 1.881

2.080 3.979 1.399

0.433 0.822 1.495

. 1.144 1.261 1.908

0.875 1.101 2.313

0.667 0.618 1.341

2.744 1.729 2.051

1.929 4.449 1.470

1.647

95% confidence range (3. 8) (3. 7)

. o. 08 0.17 0.44

0.12 0.07 0.39

0.12 0.09 0.21 0.14

0.37 0. 40 0.22

0.22 2.38 0.31

0.40 0.12 0.05

0.11 0.21 0.58

0.14 0.08 0 .. 45

0.19

0.34

0.56

0.25

0.71 2.37 0.40

0.08

22

In these runs, the~ value are greater than 30 or more (see tables of each run in Appendix B). Therefore, the calibrated L ff is not suitably used in these cases. (see General Discussion e in Appendix D).

In 3-variable search, some systems fail to run by using DA from 2-variable r~sult and~ =24.98 from calibration run. Thes~ values are not listed in this Table. (see Appendix. B~ Results of each run).

Page 36: Determination of molecular diffusivities in liquids

23

probably soak up more solvent, if the viscosity of the solvent is

low. It is also known that some of the high viscosity systems

were heated to speed the soaking process and some were not. The

effect of temperature and time of soaking as well as the relative

solute-solvent viscosity may play an important role in determination

of Leff and, consequently, the molecular diffusivities by using

Equation (3. 7) for long time diffusion periods.

In the determination of molecular diffusivities by using

Equation (3.7) with highly viscous systems, the Leff value which

should be used probably should be less than the values of Leff

determined from the NaCl-water calibration runs (about 0.531 em)

but greater than L, where L is the physical distance from surface

to the center of the frit. Therefore, Leff (about 0.531 em) and

L (0.317 em) were both studied in this work as possible limiting

cases. The values of DAB obtained by using these two values of

mass transfer length in Equation (3o7) for two-variable and three­

variable searches are shown in Table 3 and 4. In the least-squares

analysis, using the physical distance of the frit (0.317 em) will

decrease the calculated diffusivity about 64% compared with the

diffusivity calculated using Leff (about 0.531 em from calibra­

tion runs). The reason for this difference is ·that the least­

squares curve-fitted diffusivity is proportional to the square of

the value of mass transfer length used in run.

Since the possibility exists that Leff determined from the

calibration runs with dilute aqueous salt solution may not be the

same as in _the high viscosity diffusivity runs, results from the

Page 37: Determination of molecular diffusivities in liquids

24·

Table '+

Experimentally Predicted Molecular Diffusivities

Using Long Time Equation with L t ---- ---- -ac

Solute Solvent Temp /JB 6 A B oc cp DAB x.lO 95%

2 confidence em /sec range

(3. 8) (3. 7) (3. 8) (3 0 7)

ethylene ethylene 25.0* 16.60 0.883 0.666 0.09 0.11 glycol glycol 30.0* 13o56 0. l.J.9 6 0.'+3'+

'+0.0 9. '+1 0.613 0.620 0.16 0.19 50.0 6.77 1. '+73

ethylene diethylene 25.0* 27.16 o. '+13 glycol glycol 30.0 21.61 0.356 0.357 0.03 0.03

'+0.0 11+. 35 0.686 0.751 0.15

* ethylene propylene 25.0* '+3.36 0.'+13 O.l.J.l'+ 0.05 0.05 glycol glycol 30.0 32.62 0.196 0.1'+7 0.02 0.06

'+0.0 19.56 0.'+1+6 0 .1+36 0.07 0.11 50.0 12. '+0 1.113 0.05

cyclo- ethylene 26.6 16.60 0.86'+ 0.914 0.13 0.11 hexanol glycol 30.0* 13.56 0.998 0.935

40.0 9. l.J.l 0.670 0.666 0.08 0.08

cyclo- diethylene 26.6 27.16 0.741 0.631 0.08 0.22 hexanol glycol 30.0* 21.61 1.117 1.189

40.0 14.35 o. 498 0.'+78 0.12 0.13

* cyclo- propylene 26.6 4-3.36 1.108 1.093 0 .l.J.3 0.15 hexanol glycol 30.0 32.62 0.306

40.0 19.56 0.532 0.535 0.08 0.08

* In these runs~ the ~ values are smaller than 30 or less (see table of each run in Appendix. B). Therefore, the actual length of the frit which is 0.317cm is not suitably used in these cases (see General Discussion in Appendix D).

Page 38: Determination of molecular diffusivities in liquids

25

short contact time analysis (Equation (3. 9) with weighting factor)

are recommended as most reliable.

Because of the possibility of Leff being different for low

viscosity solventsand high viscosity solvents, a modification of

the least-squares analysis of Equation (3.7) for determination of

the molecular diffusivity was attempted. In this approach, the

effective mass transfer length \vas considered as a curve-fitting

parameter as well as DAB in the diffusivity runs. This may be

done by substituting the right-hand side of Equation (5.1) foro<' in

Equation (3.7). The non-linear least-squares technique of this

modification will be described in more detail in Appendix D.l.

The diffusivities determined by this modified me·thod are listed

in Table 5 and cCJmpared with other results in Table 6. These

results show that diffusivities obtained are more accurate than

the results obtained by considering Leff (determined from the low

viscosity calibration experiments) as a frit constant in diffusi­

vity runs. It is also found that the values of Leff obtained

varied from run to run--ranging from 0.582 to 0.32~ em (see Tables

B.l9 to B.2~). For some of the systems, the least-squares

analysis did not converge; however, the use of this procedure

still seems very promising because the need for calibration

experiments is eliminated.

The molecular diffusivities determined for six high viscosity

systems by using Equation (3.9) with the weighting factor are on

the average 3.85% greater than the values by using equation with­

out weighting factor. The average value of AAPD for the ~9

Page 39: Determination of molecular diffusivities in liquids

26

Table 5

Experimentally Predicted Molecular Diffusivities

Using Long Time Equation with 1eff ~ Parameter

Solute Solvent Temp fJB DAB X 106 95%

A B oc cp 2 confidence em /sec range

(3.8) (3. 7) (3. 8) (3. 7)

ethylene ethylene 25.0 16.60 1.120 1.088 0.02 0.02 glycol glycol 30.0 13.56 1.438 1.358 0.00 0.06

40.0 9.41 1.585 1.570 0.43 0.32 50 .. 0 6.77 2.500

ethylene diethylene 25.0 27.16 0.681 0.657 0.08 0.11 glycol glycol 30.0 21.61 0.840 0.857 0.16 0.22

40.0 14.35 1.014 1.052 0.22 0.28

ethylene propylene 25.0 43.36 0.596 0.565 0.06 0.08 glycol glycol 30.0 32.62 0.642 o. 643 0.03

40.0 19.56 0.936 0.909 0.08 0.07 50 .. 0 12.40 1.563 0.01

cycle- ethylene 26.6 16.60 0.811 0.880 0.03 0.01 hexanol glycol 30.0 13.56 0.823 0.869 0.00

40.0 9.51 1.388 1.366 0.09 0.09

cyclo- diethylene 26.6 27.16 0.587 0.579 0.03 0.01 he:x.anol glycol 30.0 21.61 0.547 0.647 0.03 0.03

40.0 14.35 1.127 1.090 0.01 0.03

cycle- propylene 26.6 43.36 0.146 0.146 hexanol glycol 30.0 32.62 0.412 0.00

40.0 19.56 o. 740 0.730 0.01 0.02

Notice: In running these results using long time equation, Leff was considered as a curve-fitting parameter. This will be discussed in more detail in Appendix D.l.

Page 40: Determination of molecular diffusivities in liquids

Solute

A

* ethylene glycol

ethylene glycol

ethylene glycol

MPD (1) MPD (2)

cyclo­hexanol

cyclo­hexanol

cyclo­hexanol

MPD (1) MPD (2)

Solvent

B

* ethylene glycol

diethylene glycol

propylene glycol

ethylene glycol

diethylene glycol

propylene glycol

MPD (1) (5 systems) MPD (2) (5 systems)

27

Table 6

Comparison of Experimentally ~i~ Molecular Diffusfvities

with Various Correlation· Equations

Mitchell 6 2

D x 10 , em /sec Wilke-exp B

cp --------------------------------------~C~h•ang short time models long time model Dwc

(3.10) (3.9) (3.9) (3.8) (3.7) (3.8) (3.7) --

25.0 30.0 40.0 50.0

16.60 13.56

9.41 6.77

w

1.151 1.501 1.818 2.442

1.040 1.278 1.409 2.416

w

1.131 1.330 1.516 2.491

25.0 27.16 0.739 0.614 0.664 30.0 21.61 0.973 0.720 0.763 40.0 14.35 1.175 0.852 0.913

25.0 43.36 0.686 0.519 0.585 30.0 32.62 0.791 0.627 0.645 40.0 19.56 1.146 0.847 0.902 50.0 12.40 1.487 1.530 1.502

26.6 16.60 0.701 0.755 0.749 3o.o · 13.56 o.960 n.862 o.886 40.0 9.41 1.438 1.272 1.301

26.6 27.16 0.612 0.601 0.616 30.0 21.61 0.792 0.626 0.653 40.0 14.35 1.230 1.076 1.102

26.6 43.36 0.183 0.180 0.181 30.0 32.62 0.480 0.392 0.404 40.0 19.56 0.858 0.692 0.714

Leff constant Leff.variable ~B=l.O ~=8

1.108 1.144 1.184 l. 261 1. 720 1.908 4.138

1.120 1.438 1.585 2.500

1.088 1.350 1.570

·' " !

0.847 1.001 1.972

0.875 0.681 0.657 0.673 0.462 0.616 0.472},§.628 0.456 0.608 O.IUO 0.51J6 0.396 0.528 1.101 0.840 0.857 0.860 0.584 0.779 0.569'0.794 0.567 0.768 0.499 0.666 0.502 0.607 2.313 1.014 1.052 1.338 o.889 1.182 o.906 1.208 o.879 1.112 o.706 o.91J2 0.112 1.029

0.674 o. 695 1.255 3.124

0.667 0.596 0.618 0.642 1.31+1 0.936

1.563

0.5•65 0.357 0.321 0.482 0.324 0.432 0.318 O.ll-24 0.24-2 0.322 0.279 0.373 0.64-3 0.482 0.423 0.562 0.428 0.670 0.4-20 0.560 0.278 0.370 0.374- 0.499 0.909 0.831 0.699 0.930 0.706 0.941 0.694 0.925 0.385 0.511J 0.635 0.846

1.353 1.096 1.412 1.106 1.548 1.088 1.451 0.550 0.733 1.018 1.357 20.21 25.55 11.40 24.98 11.64 26.52 12.07 '45:1i5 28.33 3iT.'S'2 18.24 23.33 22.21 12.71 22.28 10.01 23.35 13.41 41.67 25.75 30.36 15.50

2.462 2.744 0.811 0.880 0.586 0.613 0.815 0.708 0.943 1.575 1.729 0.823 0.869 0.729 0.770 1.025 0.885 1.179 1.881 2.051 1.388 1.3.66 1.086 1.159 1.54-1 1.320 1. 760

0.389 0.519 0.912 1.216 0.456 0.609 1.125 1.500 0.705 0.940 1.642 2.190

2.080 1.929 0.587 0.579 0.468 0.310 0.465 0.32~ 0.4-32 3.979 4.1+49 0.649 0.61+7 0.598 O.IJ.OO 0.535 0.416 0.561J 1.399 1.470 1.127 1.090 0.930 0.629 0.840 0.654- 0.873

0.433 0.822 1. 495 1.647

0 .11~6 0.412 o. 74·0

O.l!J6 0.24-8 0.244 0.325 0.262 0.3,4-9 0.355 0.328 0.437 0.351 lh~68

0. 730 0.578 0.555 0. 74-0 0.591 O\'i89 19.67 27.21 22.30 22.943'1)."8s 17.16 26.23 22.89 22.46 31.42

0.34-1 0.455 0.434- 0.579 0.383 0.511 0.551 0.734 0.631 0.81Jl 0.842 1.123

0.151J 0.205 0.313 0.418 0.183 0.244 0.419 0.558 0.308 O.IJ10 0.705 0.941 'ij5.77 28.25 24.62 45.97 43.55 27.07 25.01 49.31

19.91J 26.38 16.85 23.96 21.25 26.52 12.07 45.61 28.29 29107 32.60 20.21J. 21J.22 17.80 22.37 20.72 23.35 13.41 42.61 26.41 27.68 32.40

* Notice: Self-diffusion coefficients are listed only. DiffusivHy calcula- 3) n1 are the values using Kistiakowsky's equation in predicting the heat of.vaporization of compounds, n2 from Mitchell's ratio, and n3 from Bondi-Simkin's 'Tap1e of heat of vaporization.

tion using mutual diffusion correlation equations will be listed in Table C.7.

l)MPD(l) indicated the average absolute percent deviation of values of each correlation from experimental values of Equation (3.9) with weighting factor in Equation (q. 2) , and MPD (2) without weighting factor. "w" always means \'lith weighting factor.

2) Except the experimental diffusivities, the diffusivi'tie•s listed in run temperature 26.6 were actually calculated at 25.0°C.

I+) n!J are calculated using Mitp,hell's experimental va1~es·of free energy of activation, and ~are calculated using f - 0.99. (see sample cal~ation in A;?peridix C) •.

Page 41: Determination of molecular diffusivities in liquids

diffusivity runs using Equation (3.9) with the weighting factor

is 4. 84% and 5. 84% for the case without the weighting factor.

The experimental molecular diffusivities determined in this

study of the short time equations and the long time equation are

compared with values predicted by various. correlation equations

in Table 6. The detailed discussion and comparison of results

from Equation (3.9) with the weighting factor with the various

correlation equations can be found in the following subsections.

The test of self-diffusion method with the ethylene glycol

data will be made in Appendix C.l+.

5.1 Empirical Prediction of Diffusion Coefficients

The most successful empirical equation is that suggested by

Wilke-Chang(l5). It is based primarily on data with solvent

viscosities between 0.4 and 1.5 centipoise. Its applicability

for high viscosity data has not be extensively detennined. The

form they proposed is

28

* (5. 2)

where ~B· is a variable~ characteristic of solvent B~ and called

nassociation nurnber11 for the solvent. The two limiting values of

lf B are 1.0 (unassociated solvents) and 2.6 (water as solvent) as

given by Wilke-Chang are used in this work.

* For an explanation of notation see the Nomenclature section, and for sample calculation see Appendix C.l.

Page 42: Determination of molecular diffusivities in liquids

29

The molecular diffusivities predicted using \vilke-Chang

equation with \f' B = 1. 0 and 2. 6 are included in Appendix C.l and

compared in Table 6. For five systems of mu·tual diffusion studied,

the AAPD of Wilke-Chang values from the experimental values using

Equation (3. 9) with the weighting factor (denoted by "w'') and

without the weighting factor are summarized as follows:

lfB

1.0

2.6

2 systems ·(ethylene glycol as solute)

20.36 (w)

23.24-

61.4-4 (w)

71.55

3 systems (cyclo­hexanol as solute)

19.67 (w)

17.17

62.73 (w)

4-5.95

total 5 systems

20.00 (w)

20.25

61.93 (w)

58.25

It is seen in Table 6 that application of the ~.\Tilke-Chang

( tp B = 1. 0) correJ ation to these viscous systems frequently leads

to predicted diffusivities lower than the experimental values,

except for the system of ethylene glycol diffusing in diethylene

glycol. This breakdown is not entirely surprising as the empiri-

cal terms in the equation were not developed using data for

viscous systems. However, for an over-all observation for five

systems studied in this work, an association number of 1.0 seems

appropriate~

Page 43: Determination of molecular diffusivities in liquids

30

5.2 Gainer and Metzner Estimation Technique

Gainer and Metzner(7)have developed the following equation

for predicting DAB starting with the Eyring absolute rate theory:

kT N % E -EDAB ( ) ( 1-C 2B 2 ) -v;- ex.p RT * (5.3)

The quantity (Ep- ED) may be estimated from heat of vaporiza­

tion data and from molecular sizes (see Appendix C.2). Heat of

vaporization data studied in this work were calculated by using

Kistiakowsky's Equation (13, Appendix C.2) as well as from

experimental values of Bondi and Simkin1 s Tables 6 and 7(4), and

from Mitchell's Thesis(l2) •. These values are included in Appendix

C, Table C.2.

The terms in Equation (5.3) is an arbitrary packing para­

meter usually taken as 6.0ClO). Gainer and Metzner(]) reported~

may be estimated from self-diffusion data. If self-diffusion data

are not available, it may be assumed thats = 6.0 for most non­

associating liquids and 5 = 8.0 for such liquids as ethanol~

methanol, and.glycol. These two extreme values were both used in

this work as limiting conditions. The results of these predictions

are included in Appendix C.2, Table C.S, and compared in Table 6.

For five systems studied in this work, the AAPD of predicted DAB

from. the values obtained by using Equation (3. 9) with and wi·thout

a weighting factor are summarized in the following table. The

* See Appendix C.2 for sample calculations.

Page 44: Determination of molecular diffusivities in liquids

source of the heat of vaporization data is indicated as: '' 1n

denotes the values calculated from Kistiakowsky's equation(l3),

31

''2'' from Nitchell's thesis and n3rr from Bondi and Simkin's Table

6 and 7.

Source of 2 systems 3 systems total 5 (ethylene (cycle- systems

4H glycol as hexanol as vap solute) solute)

6.0 11.64- (w) 30.85 (w) 21.24- (w)

1 6.0 10.01 31.4-2 20.75 8 .. 0 24-.94- (w) 22.94 (w) 23 .. 96 (w) 8.0 22.28 22.4-5 22.36

6.0 11.4-0 (w) 22.30 (w) 16.85 (w)

2 6.0 12.71 22.90 17.80 8.0 22.55 (w) 27.21 (w) 26.38 (w) 8.0 22 .. 21 26.23 24-.22

6.0 12.07 (w)

3 6.0 13.34-8.0 26 .. 52 (w) 8.0. 23.35

It is found in this study that using 5 = 6. 0 in Equation

(5.3) predicted better results that 3 = 8 .. 0. However, using

different sources of heat of vaporization data produces different

results (see Table 6). For the two systems using ethylene glycol

as the solute, the above three different sources of the heat of

vaporization data can be used to predict ·the molecular diffusivi ties

with about the same results--accurate to about ~ 12% with 5 = 6.0

in Equation (5.3). For three systems using cyclohexanol as the

solute, heat of vaporization data calculated by Mitchell from

Bondi and Simkj_n' s suggested method ('+)using critical properties

of the solute and solvent predicted better results than heat of

Page 45: Determination of molecular diffusivities in liquids

32

vaporization data calculated from Kistiakowskyts equation. Since

heat of vaporization data for cyclohexanol and its homomorph are

not.reported by Bondi and Simkin, calculations are not performed

for systems using cyclohexanol as the solute. For an over-all

observation for five systems, the results based on Equation (5.3)

were better using the values of .6H calculated by Mitchell vap

than those calculated using the Kistiakowsky equation.

5.3 Mitchell Estimation Technique

Mitchell(l2) has developed an equation for predicting DAB

using free energy of activation. The form is

2/3 D = J5L (.[2 VB) (- ~FD,AB _,

AB ~h ~ N e~ ~ 7 (5. 4)

where AFD AB can be calculated from the following equation '

(5.5)

where f is the ratio of activation energy due to hole formation

to the total activation energy in the diffusion process.

When using Equations (5.4) and (5.5) in the prediction of

*

*

molecular diffusivities, the two factors ~ and fmust be known.

However, the exact values of 5 and f are not available. Therefore,

in this study, different values of 5 are tested. They are 6.0,

7.0, and 8.0. The prediction of molecular diffusivities using these

* See Appendix C.3 for sample calculation.

Page 46: Determination of molecular diffusivities in liquids

33

three 5 values and various f are performed in this work using

Equations (5.4) and (5.5). The AAPD of the predicted diffu-

sivities from the experimental values of Equation (3.9) with the

weighting factor are calculated and plotted in Figures 7 and 8 in

Appendix C.3. The calculated AAPD versus fat different S values

for the two systems using .ethylene glycol as solute and the three

systems using cyclohexanol as solute are summarized in the follow-

ing:

f 2 systems (ethylene glycol as solute)

0.97 6.0 41.99 0.98 15.39 0.99 16.86 1.00 31.41

0.97 7.0 23.06 0.98 12.32 0.99 25.09 1.00 41.42

0.97 8.0 12.30 0.98 18.3.5 0.99 34.45 1.00 48.56

3 systems (cycle-hexanol as solute)

205.55 110.79

49.81 20.45

161.89 80.68 32.64 21.42

129.15 58.45 24.65 28.46

total 5 systems

123.77 63.09 34.2ft. 25.93

92.48 46.50 28.53 31.42

70.72 38.40 29.05 33.56

It is found that the values of f which gave the lowest values

of AAPD for the three different~ values is in the range of 0.98

to 0.99 for the two systems using ethylene glycol as the solute,

and 0.99 to leOO for the three systems using cyclohexanol as the

solute. Mitchell(l2)reported the best value off as 0.90 for~

equal to six, which does not agree with the results found in this

work for studying the mutual diffusion of the sp~cified five

Page 47: Determination of molecular diffusivities in liquids

3'+

viscous solute-solvent systems. The predicted molecular diffu-

sivities using f = 0.99 and 5 = 6.0 are included in Table 6 and in

Appendix C.3, Table C.6.

Mitchell(l2)reported experimental values of free energies of

activation of diffusion process in his thesis. These values are

listed in Table C.3. The predicted molecular diffusivities using

Equation (5.4) with these experimental values are included in

Appendix C.3, Table C.6, and compared with other values from

various models in Table 6. The calculated AAPD of these values

from the experimentally predicted values using Equation (3.9) with

and without the weighting factor are summarized in the following:

2 systems 3 systems total 5 (ethylene (cyclo- systems glycol as hexanol as aolute) solute)

6.0 28.33 (w) 28.25 (w) 28.29 (w) 6.0 25.72 27.07 26.39

8.0 45. '+5 (w) 45.77 (w) 45.61 (w) 8.0 41.67 4-3.55 4-2.61

For five systems studied in this work, Mitchell suggested

Equations (5.'+) and (5.5) predicting the molecular diffusivities

with 5 =6.0 showed better results than5 = 8.0.

5.4-. The Relations of Activation Energy of Diffusion and

Diffusivi~

The molecular diffusivity is temperature dependent. This

dependency can be related through the following definition of an

energy of diffusion--which is defined as in Mitch~ll 1 s thesis(12)as

Page 48: Determination of molecular diffusivities in liquids

35

dlnDAB = -R d(l/T) (5. 6a)

or E

ln D = K - D,AB AB RT

(5. 6b)

Equation (5.6) states that if the activation energy of diffu-

sian is a constant, a plot of the logarithm of diffusivity versus

reciprocal of absolute temperature should be a straight line.

The activation energy of the diffusion process can be easily cal-

culated from the slope of the line. The molecular diffusivity at

any particular temperature can thus be predicted easily from this

relation. In this study, the experimentally predicted diffusivi-

ties from Equation (3.9) with the weighting factor at different

temperatures are curve-fitted to Equation (5.6). The results of

the calculated activation energy and AAPD of calculated diffu-

sivities from experimental values are shown in Table 7 and Figures

3 and 4. The activation energy calculated from the experimental

results of Equation (3.9) without weighting factor are also

included in Table 7. For the six systems studied, the average

values of AAPD included in Table 7 are 5.89% and 6.46% for Equation

(3.9) with and without weighting factor, respectively.

The molecular diffusivities predicted in this work by using

Equation (3.9) with weighting factor described in Equation (4.2)

are considered as the "best" results throughout this work. There-

fore, it is recommended ~hat Figures 3 and 4 be used to predict the

molecular diffusivity at any temperature desired within the range

studied.

Page 49: Determination of molecular diffusivities in liquids

36

Table 7

Experimentally Measured Activation Energy of

Di·ffusion Process from Diffusivi ties

* Solute Solvent Data Activation AAPD Energy

A B Points EDAB' Kcal/mole

(3. 9) (3. 9) w

ethylene ethylene q. 5.904 5.655 glycol glycol

ethylene diethylene 3 3.914 3.858 glycol glycol

ethylene propylene 7.804 7.226 glycol glycol

cyclo- ethylene 3 6.561 6.880 hexanol glycol

cyclo- diethylene 3 7.592 7.539 hexanol glycol

cyclo- propylene 3 15.855 16.123 hexanol glycol

* AAPD is calculated from the equation as below

AAPD =

A

1 N

where DAB = predicted from Equation (5.6)

(3. 9)

8 .. 08

1. 96

6.69

2.08

6.75

13.18

DAB = experimentally predicted from Equation (3.9)

(3. 9) w

6.96

1.31

6.37

0.85

6.13

13.74-

Page 50: Determination of molecular diffusivities in liquids

CJ OJ CJl

N"" 5

,-... l):l

r::l~ ..._, t::

,....f I

15.0

~ ethylene glycol-ethylene glycol

0 ethylene glycol-

14.5 diethylene glycol

D ethylene glycol-propylene glycol

14.0

13.5 -

13.0

12.5~------~~------~--------~--------~ 30.0 31.0 32.0 33.0 34.0

Fig. 3. Experimental relationship between diffusivity and absolute temperature (ethylene glycol as the solute in different solvents)

37

Page 51: Determination of molecular diffusivities in liquids

6 cyc1ohexanol-

15.5 ethylene glycol

0 cyclohexanol-diethylene glycol

0 cyclohexanol-propylene glycol

.15.0

14.0

14.0

13.5

13.2

30.0 31.0 32.0 33.0 34.0

1 4 (~ X 10 OK

Fig. 4. Experimental relationship between diffusivity and absolute temperature (cyclohexanol as the solute in different solvents)

38

Page 52: Determination of molecular diffusivities in liquids

39

5.5 Conclusions

The results of Sections 5.1, 5.2, and 5.3 lead to the follow-

ing conclusions:

(1) Although the Wilke-Chang equation is surprisingly good

for low viscosity, dilute solutions--usually accurate . .(10)

to about 10 percent , for five high viscous systems

of mutual diffusion studied in this work, this equation

(with <pB = 1 .. 0) is accurate within ± 20% (average abso­

lute percent deviation) when compared with the

experimental results from Equation (3.9) using the

weighting factor. It is seen in this work that the

application of Wilke-Chang correlation to these viscous

systems frequently lead to the predicted diffusivities

lower than the experimental values (for example, the

arithmetic average percent deviation was -13.73~,

· except for the ethylene glycol-diethylene glycol system

(20. 21~ • Of course, the application of Wilke-Chang

correlation depends upon the ability to either know or

assun1e an accurate value for ~ B•

(2) The use of Equation (5.3), suggested by Gainer and

Metzner, with ~ = 6 and accurate viscosity-density data

and heat of vaporization data can predict the highly

viscous solute-solvent systems accurately to within 12

percent.

(3) Mitchell suggested Equations (5.~) and (5.5) need the

information of f. However, upon choosing suitable

values of f and S , these equations can also predict

Page 53: Determination of molecular diffusivities in liquids

the molecular diffusivities accurately to 15 percent-­

as found in this work using f = 0. 99 and S = 6. 0.

Mitchell recommended f = 0.90 based on the study of

40

low viscosity systems around the value of S = 6.0 for

which the AAPD for five systems is calculated and found

to have a considerable deviation compared to the values

using f = 0.98 or 0.99 which are recommended for calcu­

lation of the molecular diffusivity using Equations (5.4)

and (5.5) for highly viscous systems.

Page 54: Determination of molecular diffusivities in liquids

41

6. Nomenclature

AT

b n

c

==

==

==

2 effective mass transfer area of the frit, em

eignvalues of eignfunction: - d..b == tan b n n

solute concentration inside the porcus frit, g-mole/ liter

Cf == solute concentration in the solvent bath, g-mole/liter

c ..... = IO

c == 0

* c ==

=

DAA ==

DAB ==

ED AB == , t.E == vap

E = ,Ll,B

E = p.,X-H

f =

initial solute concentration in the solvent bath, g-mole/liter

initial solute concentration inside the frit, g-mole/ liter

dimensionless solute concentration inside the frit,

co - c co - cfo

dimensionless solute concentration in the solvent bath,

co-l c - c o fo

2 self-diffusion coefficient, em /sec

mutual diffusion coeffi~ient, cm2/sec

activation energy for the diffusion process, cal/mole

internal energy of vaporization, cal/mole

energy to overcome viscosity energy barrier, cal/mole

activation energy due to hydrogen bonding, cal/mole

ratio of the activation energy due to hole formation to the total activation energy in diffusion

activation free energy for viscous flmv, cal/mole

activation free energy for binary diffusion, cal/mole

·activation free energy for self-diffusion, cal/mole

activation free energy due to hydrogen bonding, cal/ mole

Page 55: Determination of molecular diffusivities in liquids

4-2

6FD XX-D = activation free energy due to dispersion force bonds~ ' cal/mole

h =

AHVAP =

AHVAP ,X-H = Ll. Hv!P =

k =

~=

N =

R=

t =

T =

Tb =

v=

vf =

v = s

p =

-5 =

fB = ; =

tt =

d.. =

-27 Planck's constant, 6.623 x 10 erg-sec

heat of vaporization, cal/mole

heat of vaporization due to hydrogen bonding, cal/mole

heat of vaporization of homomorph compound, cal/mole

-16 Boltzmann's constant, 1.380 x 10 erg/deg

effective mass transfer length from the center to the surface of the frit, em

molecular weight of solvent

23 Avogadro's number, 6.023 x 10 molecules/mole

universal gas constant, 1. 98 7 cal/mole- deg

time, sec

absolute temperature, OK

normal boiling point, OK

molal volume of liquid, ml/mole

volume of solvent in the solvent bath, 3 em

volume of solvent in the frit, 3 ern

viscosity of liquid, poise or centipoise

parameter describing the geometrical configuration of the diffusing molecular and its neighbors

the nassociation nwnbern for solvent B

dimensionless distance from the center of the frit, x/L

dimensionless time, DAB t /L2

volume ratio of the solvent in the solvent bath and the frit

cJ = standard deviation Subscripts ·

A = solute

B == solvent

Page 56: Determination of molecular diffusivities in liquids

4-3

7. Bibliograph)!

1.. Amundson, N. R., nMathematical Methods in Chemical Engineering, Matrics and Their Applicationn, Prentice-Hall, Inc., Englewood Cliffs, N.J. (1966), pp. 4-1-4-3.

2. Bird, R. B., W. E. Stewart, and E. N. Lightfoot, 11 Transport Phenomenat', John Wiley and Son t s, New York (1963) , pp. 357-360.

3. Ibid., p. 558.

1+. Bondi, A., D. J·. Simkin, A.I.Ch.E. Journal, 1, 4-73 (1957).

5. Brownlee, K. A. , "Industrial Experimentation" , 4-th American ed., Chemical Publishing Co., New York, N.Y. (1953) , pp. 61-65.

6. Conte, S. D., nElementary Numerical Analysis'', McGraw-Hill Book Company, New York (1965) , pp. 43-4-6.

7. Gainer, J. L., and A. B. Metzner, A.I.Ch.E. -I. Chern. E. Symposium Series, No. 6, p. 71+ (1965).

8. Harned, H. S., B. B. Dwen, "The Physical Chemistry of Electrolyte Solutionsn, 3rd ed., Reinhold Publishing Corp., New York (1958).

9. Hollander, M. V., and J. J. Barker, A.I.Ch.E. Journal, 2,, 514- (1963).

10. Lightfoot, E. N., and E. L. Cussler, Selected Topics in Transport Phenomena, Chern. Eng. Prog. Symposium Series, No. 58, 61, p. 82. (1965).

11. Mickley, H. S., T. K. Sherwood, and C. E. Reed, nApplied Mathematics in Chemical Engineering", 2nd ed., McGraw-Hill Book Co., Inc., New York (1957), pp. 95-98.

12. Mitchell, R. D .. , Ph._D. Thesis, University of Missouri-Rolla, Rolla, Missouri (1968).

13. Smith, J. M., and H. C. Van Ness, nchemical Engineering Thermodynamics71 , 2nd ed., McGraw-Hill Book Co., Inc. (1959)' p. 132.

11+. Thomas, B. D., and W. H. John, "Advances in Chemical Engineer­ingn, Academic Press Inc. , New York (1956) , Vol. 1, p. 156.

15. Wilke," C. R., and P. Chang, A.I.Ch.E. Journal, 1, 264- (1955).

Page 57: Determination of molecular diffusivities in liquids

APPENDIX A

Least Squares Analysis of Mathematical Models

The following is a development of the equations necessary to

solve the system parameters using either a linear or non-linear

least squares technique in terms of the given mathematical models

of the porous frit problem.

Page 58: Determination of molecular diffusivities in liquids

4-5

A.l Linear Eguation (3 .10)

Equation (3 .10) is in the fonn

4- A.r c 0 Jn AJ3 t cf = + cfo (A.la)

1-rr vf

in which parameters are ~ and Cfo in calibration runs or DAB and

Cfo in other runs. Take calibration run for example,

Let

(a constant) (A.lb)

therefore, Equation (A.la) becomes

(A.lc)

According to least squares criteria, use Equation (2.3) which is

(A.ld)

A in which Cfi (i = l, 2, ---N) are predicted values and Cfi are

measured values.

Case I. W. = 1, that is the Equation (2.2) ~

Then

N

s = ~ i = 1

(A.le)

Page 59: Determination of molecular diffusivities in liquids

46

According to Equation (2.6), take the partial derivative to AT and

cfo and set the equations equal to zero. Therefore,

N N N

~ ~ ~ ~ ~ (kt .) A.r+ t. 2 c = t. 2 cfi

i = 1 l i = 1 l fo i = 1 l (A.lf)

N N N 2. ~

~ 2 (kt. 2) A.r+ cfo = cfi i = 1

l• i = 1 i = 1

(A.lg)

Solving Equations (A.lf) and (A.lg) simultaneously, one can find

Case II. ~

and u = K1 (Cfi) 2 where K1 is a constant.

Equation (A.le), therefore, becomes

N

s = ~ l (A.lh) i = l

and Equations (A.lf) and (A.lg) become

N N ~ N ~

kt. ~

t. 2

~ 1·

___,;;!:., • A + l ·c ~ = t. i = 1 cfi T i = l cfi fo i = 1 l

(A.li)

N . 1

N kt.~ ~ l ~ 1

cfo N -·A.r+ . = i ;;: 1 cfi i = 1 cfi

(A.lj)

Solving Equations (A.li) and (A.lj) simultaneously, one can find

AT and Cf0 • (see Appendix G, Program No. 1)

Similarly, we can follow the same technique to calculate the

molecular diffusivities. (see Appendix G, Program No. 1)

Page 60: Determination of molecular diffusivities in liquids

47

A. 2 N.on-Linear Equation J]~

Equation (3.9) is in the form

c - c (exp 4 Arr 2 DAB t J (1 -erf 2 A,: DAB t J f 0 = c - c v 2 vf fo 0 f

(A. 2a)

where the error function is defined as

2 2 lx

erf (x) = fTf exp ( -?{_ ) d ~ (A. 2b)

For example, in the calibration runs, the parameters are AT and

Cfo" We let

Equation (A.2a) becomes

= B

= Y. 1

=X. 1

A2x_2

Yi = Be· 1 ( 1 - erf (AXi)J

(a parameter)

(a parameter)

(A. 2c)

(A. 2d)

Using a TaylorTs Series expansion (Equation (2.7)) to linearize

Equation (A.2d) about the estimated initial estimates of B and A ~ 0 0

one obtains

Page 61: Determination of molecular diffusivities in liquids

A 2x 2 y. = B e 0 i ( 1 - erf (A X .)"1

J. 0 OJ.J

2

fif B (X.) (A - A )

0 l. 0

Further let

2 2 2 A X. E. - fTr X. =D.

0]. l ~~~ ]. ].

A - A = !:::.A 0

B - B = Cl.B 0

(correction term)

(correction term)

Therefore, we have the following linearized form

Y. = B E • + E. A B + B D . ( A A) ]. 0 l l 0 l.

'+8

(A. 2e)

(A. 2f)

(A. 2i)

Using the least squares tecrmique based upon E~Jations(2.2) and

(2.6), we obtained

N N

( 2 (B D . ) 2J A A + ( 2 (B E • D • ) ] A B = i = 1 ° l. i = 1 ° ]. l

N

~ B D. (Y. - B E.) . - 1 0 l l 0 l l -

(A. 2j)

Page 62: Determination of molecular diffusivities in liquids

N N

( ':>-: (B D.E.)) AA + ( 2 (E~) 2)bB = . - 1 ° ~ ~ . - 1 ~ l - l -

N

L i = 1

E. (Y. - B E.) l ~ ·0 ~

'+9

(A. 2k)

The correction terms, t:J..A and AB can be solved simultaneously

from the Equations (A. 2j) and (A. 2k). The iterative procedure may

-9 be repeated as the correction terms approach zero (1.0 x 10 was

used in this work). (see Appendix G~ Program No.1)

s~~ilarly, runs for calculations of the molecular diffusivi-

ties can be performed. (see Appendix G, Program No. 1)

A.3 Non-Linear Equation {3.7)

The form used for the two variables analysis is form (3.8)

CX)

~ (A.3a) n = 1

where

(A. 3b)

For example, in calibration runs, the parameters are~ and L.

(where Lis Leff). In this case, the value of Cfo is taken to be

a constant and equal to the value determined from Equation (3.9).

For the least squares analysis, Equation (A.3a) may be simplified

by letting

Y. l

Page 63: Determination of molecular diffusivities in liquids

50

c - c = G (a constant) 0 fo

(A. 3c) DAB

= E (a parameter) L2

Linearize Equation (A. 3a) about the estimated initial values~

0( 0 and E 0 , by using Equation (2. 7) • Therefore

_Y_i_ = -=1- - 2 i G l+o{o n = 1

o( ( -E b 2t ) o exp o n i

1+ o(. 2b 2 + d.. , o n

+5~-l t (1+ o( ) 2

0

o<J

- 2 ~ ----=1--:--­n = 1 (1 + o( + o{ 2b 2) 2

o o n

db

(A. 3d.)

The term ( dr;Xf!) was neglected in this work. The reasoning for

this is as follows (see also Appendix D.2):

bn are the non-zero roots of - o{ bn = tan bn (n = 1, 2, ---oO),

and - ~ is the slope of the curve of tan b versus b • In this n n

study, cJ.. is defin_ed as the volume ratio .of the solvent in the bath

and the frit, respectively, and is considered a large value (25 to

4-5). Therefore, the b values are a weak function of ct (see n db

Appendix D. 2) • The value of ( dd...n) in the range of o( from 25 to 4-5

Page 64: Determination of molecular diffusivities in liquids

51

is calculated to be about 0.0004 (see Appendix D.2). The numeri-2 db

cal values of (2o( b1 ) and (2o( b1 dot ) using o( = 25.0 are

calculated as 178 and 0.032, respectively. \~en these bvo values

are compared with 1.0 which is in Equation (A. 3d), one can see the db

n effects of(d~ )can be neglected. After simplification, Equation

(A. 3d) becomes

Y. l

G

-E b 2t. - ( o( e o n l) (1. + 2 o( b 2) )~

o o n ] (o/. _ o( )

(1 + o( + d.. 2b ) 2 0 o o n

(A.3e)

o( -E b 2t } o [(bn2tl.) e o n iJ (E

l+o( +o< 2b 2 o o n

- E ) 0

Further let

o<o -----~~---~ = AK l+ol +~' 2b 2 n

o 0'\o n

E b 2t. = (pc ) . on 1 n 1

Exp ( -pc ) . = (BK ) . n 1 n 1

1 l+o( = Fl

0

. , E-E =.tiE 0

(A.3f)

Page 65: Determination of molecular diffusivities in liquids

52

therefore, Equation (A.3d) becomes

Y. _1:.= G

Od Fl- 2 ~

n = 1 (AK ) (BK ) .

n n 1 -[2 ~ (_L (AK ) (BK ) • _ 1 o( n n1 n - o

l (AK ) 2 (BK ) . (1+2o( b 2)) + (Fl) 2J(c.o!) o<o n n 1 o n

c.;,

+ { 2 ~ (AK ) (b 2t .) (BK ) ·} (.A E ) n n 1 n 1 n = 1

(A. 3g)

For nin fixed, one can calculate the following infinite series as

oO

22. n = 1

(AK ) (BK ) • = P • n n 1 1

C>O

2 ~ (_l_ (AK ) (BK ) . - l (AK ) 2 (BK ) • (1 + 2 o( b 2)~ -.1 n n1 -.~ n n1 on n = 1 V\o '-"o

oGl

2 ~ n = 1

= Q . l

(AK ) (b 2t .) (BK ) • n n 1 n 1

== R. l

(A. 3h)

In -this work, the eignvalues of b were calculated by using n

the recursion formula: b11 = b1+ (n-1)1f (n = 2, 3, ---00) (see

Appendix D.2). However, upon running the data, it is found that

maximum number of terms need not exceed ~0 because when increasing

the value of b , the summation term decreases quickly. ll

Using Equation (A.3h), Equation (A.3g) becomes

Y. _1:.= G (A.3i)

Page 66: Determination of molecular diffusivities in liquids

53

Equation (A.3i) is the linearized form. Further let

Fl - P. = Pl. ]. l.

(Fl) 2 + Q. = Q. l. ].

(A. 3j)

R. = Rl. ]. ].

therefore~ Equation (A~3i) becomes

'Xi = (Pl) i (G)- (Ql) i (G) (Ao( ) + (Rl) i (G) (A E) (A. 3k)

In least s_quares sense, we use Equations (2.2) and (2.5); then we

obtained the equations

N N

~ i = 1

(G) (Ql) ~(Ao() -. l.

~ i = 1

(G) (Rl) • (Q1) • (A E) ]. l.

N

= ~ ((G) (Pl). (Ql) .-Y. (Ql). . 1 l. l.l.]. ]. =

(A. 31)

N N 2 ~ (G) (Rl). (Ql) . (Ari) - L (G) (Rl) . ( AE)

i=1 l. J. i=l ].

N

= i ~ 1 ((G) (Pl) i (Rl) i - (Yi) (Rl) i J (A. 3m)

where N is the number of data points used in run. The correction

terms, ~ c( and h. L can be solved simu1 taneously from the Equations

Page 67: Determination of molecular diffusivities in liquids

54-

(A.31) and (A.3m). The iterative procedure may be repeated as the

correction terms approach zero. (see Appendix G, Program No. 2)

Similarly, runs for calculation of the molecular diffusivities

can be performed. In this case, the curve-fitting parameters are

DAB and d.. • (see Appendix G, Program No. 2)

For three-variable search, the form of Equation (3.7) is used,

where the parameters are Cfo, d..., and L in calibration runs.

Equation is in the form

Let

= 1 - ( 1 ~eX.

C - C = G o fo

Y. ~

(a parameter)

therefore Equation (A.3n) becomes

( 1 00 2o(

Y. = G - G 1 + ~ - 2:_ 2 2 exp l "" n=ll+c{+o(b

n

exp

(A.3n)

(A. 3o)

(A. 3p)

TaylorT s series expansion about G , cJ,. and E (using Equations 0 0 0

(A. 3c) , (A. 3f) , (A. 3h) , and (A. 3j)) we have the linearized form as

Page 68: Determination of molecular diffusivities in liquids

55

Y. = (G - G (P1).J +(1 -(P1).J.AG l 0 0 l l

(A. 3q)

Again using Equations (2.2) and (2.6) ~ we obtained

N N Z (G0 ) (Q1) 1. (1-P1) 1. 6d.. - ~ (G ) (Rl) . (1-P1) . .C.E

i=1 i=1 0 l l

N

i = 1 b G = 2 (y .-G + (G ) (P1) ·J (1-P1)

i = 1 l 0 0 l +

(A. 3r)

N N 2 (G ) (Q1)2• AcX- ~ (G ) 2 (Rl) . (Q1) • AE

i=1 0 l i=1 0 l l

N N + 2 (1-P1). (G) (Q1). (LlG) = 2 r0r.-G -(G)

i = l . l 0 l i = l~ l 0 0

(A. 3s)

N N ~ (G } 2 (Ql) . (Rl) . Ao{ - 2_ (G ) (Rl)2• t!.E

i=1 0 l l i=1 0 l

N N

+ ~ (1-Pl) . (G ) (Rl) . ( 6.G) = . - l l 0 l l -

~ (Y.-G - (G ) (P1) ~ . - 1 l 0 0 l l -

• (G ) (Rl) . 0 l

(A. 3t)

Page 69: Determination of molecular diffusivities in liquids

56

The correctionterms,LlG, flo(and6L can be solved simultaneously

from Equations (A. 3r) ~ (A. 3s) and (A. 3t). The. iterative procedure

is repeated as the correction terms approach zero. However, the

iterative procedure may be controlled by using the AAPD; that is,

when its value reaches a minimum the process is te1~inated. (see

Appendix G, Program No. 2).

Similarly, run for calculation the molecular diffusivities can

be performed. (see Appendix G, Program No. 2)

Page 70: Determination of molecular diffusivities in liquids

57

APPENDIX B

Results of Calibration and Other Runs

This appendix contains the results of all runs-calibration the

frits, and determination of the molecular diffusivities.

As an example of the data, the relation between concentrations

and the square root of time for

(1) Run 1, sodium chloride diffuses through water;

(2) Run 76, ethylene glycol diffuses through ethylene glycol

is plotted in Figures 5 and 6.

The experimental concentrations and curve-fitted data by least

squares analysis of these two sample runs will be included in this

appendix. The results of other 66 runs may be obtained by writing to

Dr. R. M. Wellek, University of Missouri-Rolla, Rolla, Missouri.

The following notations and symbols will be used in tables

through this appendix:

ncalibrated Lef/ - Calibrated Leff as a constant in

diffusivities runs.

" (3 .10) n - Results obtained from Equation (3 .10) •

-' (3. 9) n - Results obtained from Equation (3. 9) •

n (3. 8) '' - Results obtained from Equation (3. 8) , two-variable

search.

11 (3. 7) n - Results obtained from Equation (3. 7) , three-variable

search.

With weighting factor in the form of Equation (4.2).

11 *n - Result was not accepted because of large MPD.

If _TT - Result was not obtained because it failed to con-

verge in 40 iterations.

Page 71: Determination of molecular diffusivities in liquids

~l Q)

-1-1 •r-1

~ Q)

r-1 0 s I

bO

1.0 0 r-1

X

4-1 t.l

4-0

0

30

20

10

experimental data short -time Equation (3 .10) with weigh-ting factor

long time Equation (3.7), three-variable search

'?

0~--~----~----~----~----~--~----~----~----~--~~~~----~ 0 20

Fig. 5.

4-0 60 80

:!,: t 2 , sec

Concentration versus square root of time (Run 1, sodium chloride - water at 25°C)

120

ln 00

Page 72: Determination of molecular diffusivities in liquids

16

12

H Q)

.j...J •r1 r-l '-. 8

Q)

r-1 0 E I bO

" 0 r-1 4-x 4-;

u

0

0

~

0

r -- ____ T_____ ~---- -r

experimental data

short time Equation (3.9) with weighting factor long time Equation (3.7), three-variable search

100 200 ;!,:-

t2, sec

300

Fig. 6. ·Concen-tration versus square root of time (Run 76, ethylene glycol - ethylene glycol at 4-0°C)

400

Ln 1.0

Page 73: Determination of molecular diffusivities in liquids

60

Table B.l

Results of Calibration Runs (Equation 3.10)

Run Frit No. of A.r' 2

c~ ,g-mole/liter em MPDa . .LO ..

No. No. Data (3 .10) (3 .10) (3 .10) (3 .10) (3 .10) (3 .10)

w w w

1 1 9 10.98 10.88 0.965 1.102 1.82 2.22

2 1 9 11.16 11.20 0.838 0.840 3.63 3.57

3 2 8 14.22 14.32 0.965 0.694 3.5 6 4-.24-

4- 2 10 10.5 4- 10.67 -0.326 -0.421 6.59 6.69

5 3 8 10.45 10.50 -0.022 -0.509 4. 33 4-.39

6 3 10 11.70 11.87 -1.040 -1.191 5.63 6.72

7 q. 10 11.24 11.4-2 0.122 -0.515 3.33 4.39

8 4- 9 9. 84- 9.66 -0.582 0.871 2.71 3.34-

9 5 7 11.96 11.26 -2.05LJ- -1.054 1-J-.81 10.4-5

10 5 9 9.78 9.61 -1.4-30 -1.172 5.73 7.01

12 l 10 11.34- 11.32 -0.727 -0.678 5.08 5.18

13 6 11 9.90 9.68 -0 0 949 -Qo666 6.43 9.54

14- 6 7 10.91 10.59 -2.582 -0.216 3.96 6.55

lOS l 8 10.06 10.11 0.153 0.130 5. 34- 5.36

106 2 10 9.82 9o40 -·0. 865 -0.4-20 6.25 9.97 * 107 6 5 13.14 12.55 -4.533 -3.890 0.78 31-i-.86

108 4- 8 9.32 9.31 o. 657 0.681 3.76 3.78

109 5 8 9.86 9.73 1.224 L'-1-27 4.00 11-.26

110 3 8 13.05 13.21 -1.065 -1.191 5.04 5.22 4.09 5.68

8 AAPD 100 N l " I ==- i~ I (CfiCfi/Cfi N

* Results were not accepted because of large deviation.

Notice: v.Then "w" is used through the work, it means weighting factor in the form described in Equation (4. 2) •

Page 74: Determination of molecular diffusivities in liquids

61

Table B.2

Results of Calibration Runs (Equation 3.9)

Run Frit No. of AT, 2

cfo , g-mo1e/ liter em AAPD No. No. Data

(3. 9) (3. 9) (3. 9) . (3. 9) (3. 9) (3. 9) w w w

1 1 9 10.95 11.03 0.996 0.897 1.91 1.63

2 1 9 11.27 11.20 0.697 0.772 3. 4-5 3.61

3 2 8 14.68 14-.40 0.4-86 0.844 4-.85 3.92

4- 2 10 10.67 10.53 -0.493 -0.374- 6.94- 6.76

5 3 8 10.53 10.4-5 -0.116 -0.058 4-. 4-8 4-.38

6 3 10 11.90 11.70 -1.285 -1.095 7. 4-9 5.81

7 4- 10 11.45 11.24 -1.445 0.067 4.71 3. 4-8

8 4- 10 9.33 11.25 0.320 -0.145 5.24 4.78

9 5 7 11.73 12.05 -1.150 -2.166 5.67 4.62

10 5 9 9.63 9.76 -1.259 -1.490 6.71 5.77

12 1 10 11.37 11.35 -0.779 -0.790 5.18 5.15

13 6 11 9.66 9.87 -0.732 -0.989 9.00 6.18

14- 6 7 10.66 10.95 -2.271 -2.656 6.61 3.64-

105 1 7 10.16 10.08 0.050 0.096 5. 4-5 5.37

106 2 10 9.39 9.78 -0.4-86 -0.980 9. 54- 6.16

107 6 5 13o-35 13.32 -4.802 -4-.774 0.73 0.74-

108 4- 8 9.37 9.36 0.597 0.602 3.88 3.88

109 5 8 9.81 9.92 1.321 1.141 4.14- 3.97

110 3 8 13.30 13.11 -1.302 -1.145 5.48 5.24-

5.65 4-.59

Explanation of notations, see Table B.1.

Page 75: Determination of molecular diffusivities in liquids

Table B.3

Results of Calibration~ (Equation 3.7)

Run Frit No. of c}., = V -rf~s 6

Lcm Cf0 xl0 g-m/1 AAPD No. No. Data

o{l ~ L L cfo,1 c 2 1 2 fo,2 1 2

1 1 16 24.010 22.065 0.564 0.649 0.996 2.136 3.501 3. 451

2 1 15 24.164 23.201 0.534 0.573 0.697 L319 3.318 2 .. 661

3 2 14 16.458 15.492 o. 614 0.670 o. 486 1.311 4. 564 3.225

4 2 17 24.713 23.754 0.555 0.597 -0.495 0.152 6.617 4.995

5 3 14 11.716 21.174 0.607 0.632 -0.116 0.165 5.691 4.658

6 3 18 '23.636 23.215 0.517 0 0 5 4-2 -1.285 -0.669 7.807 .4.134-

7 l.j. 17 23 .LW2 23 .1l~2 0.535 0.550 -0.144 0.219 5.543 3.918

8 4 16 30.276 30.211 0. 4-8 7 0. 4-95 0.320 0.5L~7 4-.367 4-.4-70

9 5 13 26.676 26.645 0.4-66 0.4-75 -1.760 -1. l!-00 3.382 4.442

10 5 15 33.24-8 32.994 O.L~70 o.tmg -1.259 -0.761 4-.64-3 6.922

12 1 15 22.226 21.773 0.566 0.596 -0.779 -0.172 8. 4-39 4-.214-

13 6 14- 26.078 25.900 0.568 0.579 -0.732 -0.533 5.051 6.782

14- 6 14- 26.4-29 26.556 0.524 0.539 -2.271 -L659 3.240 5.599

105 1 11 29.953 29.857 0.4-69 0. 4-59 0.050 -0.317 7.119 6.792

106 2 15 30.137 30.013 0.503 0. 4-98 -O.L~68 -0.676 7.514- 6.04-4-

* * 107 6 11 23.077 22.507 0. 4-81 0.553 -4-.802 -2.878 4-3.559 I 25.290 en

108 4 14- 30.625 30.552 0.510 0.506 0.597 0.432 6.762 6.065 N

Page 76: Determination of molecular diffusivities in liquids

Con:tinued

109

110

5

3

12

11

23.4-62

22.003

Table B.3

Results of Calibration Runs (Equation 3.7)

23.156

21.615

o. 631 o. 64-5

0.4-98. 0.535

1. 321 1.582

-1.302 -0.272

5.34-LJ.

7.160

5.901

4-.4-98

5.34- 4-.94-

Subscript "1" denotes two variables search using form (3.8) and 11 211 denotes three variables search using form (3.7).

* Results were not used in average value calculation.

en (JJ

Page 77: Determination of molecular diffusivities in liquids

61+

Table B.l+

Calibrated Mass Transfer Area · - ---- ----

Frit No. of Average Area A.r Standard deviation a

No. Run 2 em.

N (3 .10) (3. 9) (3 0 9) (3.10) (3. 9) (3. 9) w w w w

1 4 10.88 10.94 10.91 0.57 0.55 0.57

2 3 11.53 11.25 11.26 2.36 2.79 2.51

3 3 11.73 11.91 11.42 1.30 1.39 1.39

4 3 10.14 10.44 10.28 0.99 1.10 0.94

5 3 10.53 10.36 10.58 1.24 1.17 1.28

6 3 11.32 11.22 11.32 1.66 1.91 1. 77

* * •]:

Avg. J1. 02 11.02 10.97 0.61 0.58 0.45

~he variance denoted by <r 2would be defined by the following:

2 - 1 (X-X-)2 (J" - N-1

where X is the mean of the observed X's. N is the number of obser­vations. The square root of·the variance is termed the 11 standard deviationf1 •

* These are the standard deviations for the average ~ for each cell from the ~ for all cells.

Page 78: Determination of molecular diffusivities in liquids

55

Table B.S

Calibrated Mass Transfer Length

Frit No. of

No. Run

Average Length L ff em e

Standard deviation

N (3. 8) (3. 7) (3. 8) (3. 7)

1 lJ. 0.533 .0.569 0.04-5 0.080

2 3 0.557 0.588 0.056 0.086

3 3 0.54-0 0.569 0.058 0. OSlJ.

lJ. 3 0.510 0.517 0.024- 0.029

5 3 0 .. 522 0.536 0.094- 0.04-9

6 3 0.54-1 0.557 O.OlJ.lJ. 0.020

* Avg. 0.531 0.556 0.016 0.026

Notice: (3.8) means the values obtained from 2-variable search and (3. 7) from 3-variab1e search through this work.

*

* These are the standard deviations for the average L for each cell from the L for all cells.

Page 79: Determination of molecular diffusivities in liquids

Frit No. of

No. Run

1 4-

2 3

3 3

4- 3

5 3

6 3

Avg.

*

Table B.6

v Calibrated c:X (= V f~ Values

s

(3 .8) (3. 7)

25.09 24-.22

23.70 23.09

22.4-1 22.00

28.10 27.97

27.80 27.60

25.19 24-. 99

25.4-0 24-.98

66

* Standard deviation

(3 .. 8) (3. 7)

3.36 3.81

6.89 7.28

1.02 1.07

4-.07 4-.18

4-.99 4-.99

1.84- 2.17

* * 2.21 2. 4-0

These two values are the standard deviations for the average o1. for each cell from the o< for all cells.

Page 80: Determination of molecular diffusivities in liquids

Table B.7

Tabulated Parameters Using Short Time Equations

for Ethylene Glycol in Ethvlene Glycol

Run Frit ·Temp No. of DAB X 10 6 6 Cfo X 10 . AAPD

No. No. oc. Data cm2/sec g-mo1e/1iter (3 .10) (3. 9) (3 .10) (3. 9) (3. 9) (3 .10) {3. 9) (3. 9) (3 .10) (3 0 9) (3. 9)

w w w w w w

* 51 4 25.0 5 6 1. 734 1.024 1.164 0.025 0.057 0.042 7.65 15.19 10.35

* 52 4- 25.0 5 6 1. 780 1.090 1.24-2 0.031 0.064- 0;04-8 8.91 15.16 12.32

57 1 25.0 5 10 1.157 1.024- 1.066 0.027 0.038 0.031 3.20 4-.55 2.87

58 1 25.0 6 11 1.14-6 1.022 1.053 0.027 0.036 0.030 2.02 3.13 1.81

63 4 30.0 6 10 1.587 1.269 1. 34-2 0.027 0.046 0.034 3.63 5.91 4-.70

64- 4- 30.0 6 10 1.4-16 1.287 1.319 0.024- 0.031 0.027 9.09 4.95 5.95

69 .1 40.0 6 7 1.899 1.320 1.481 0.056 0.087 0.070 4-.34 7.42 6.82

70 1 4-0.0 6 9 1. 826 1. 294- 1. 4-10 0.050 O.Q83 0.067 2.81 7.03 6.07

75 4- 40.0 6 14- 1. 8 3 7 1. 4-6 6 1.563 0.04-7 0.075 0.058 3.12 4.4-7 3.36

76 4 40.0 6 14- l. 716 1.558 1.612 0.04-8 0.060 0.053 2. 48 2.70 2.29

81 1 50.0 6 7 2 .1+4-2 z. 4-16 2. 4-91 0.032 0.031+ 0.030 3.20 3.14- 2.66

* Results were not accepted in this work because of large deviation.

en '-.I

Page 81: Determination of molecular diffusivities in liquids

Table B·8

Tabulated Parameters Using Short Time Equations

for Ethylene Glycol in Diethylene Glycol

6 6 Run Frit Temp No. of DAB x 10 Cfo X 10

No. No. oc. Data cm2/sec g-mo1e/1iter (3 .10) (3. 9) (3.10) (3. 9) (3. 9) (3.10) (3. 9) (3. 9)

w w w w

* 54 5 25 .. 0 5 9 2.074 0.585 0.697 69.20 172.5 131.7

59 2 25.0 6 12 0.732 0.655 0.669 51.30 58.64- 55.00

60 2 25.0 6 12 0. 71!-7 0.603 0.626 4-1. 60 57.67 49.86

65 5 30.0 6 12 1.008 0.715 0.766 35.83 66.97 l~9 • 4-8

66 5 30.0 6 12 0.938 0.725 0 .. 760 4-5.49 69.37 56.65 . 71 2 4-0.0 6 8 1. 04-1 0.773 0.827 68.23 94-.38 82.66

72 .2 40.0 6 8 1.026 0.736 0.795 74.64 104.5 90.48

77 5 40.0 5 14- 1.277 0. 94-0 0.,991 90.45 121.4 107.8

78 5 4-0.0 6 14- 1.359 0.955 1 .. 04-1 74.36 118.9 94.89

* result was not accepted.

AAPD

(3~-lcl-) (3.9) w

6.50 18.13

2.60 2.69

3 .. 11 4.25

2.81 7.29

0.58 5.09

0.99 5.86

4-.80 6.61

1.76 3.76

1.71 5.62

(3. 9) w

13.22

2.30

3.86

4-.85

3.23

4.09

6.08

3 • 2L~

4.57

Q) 00

Page 82: Determination of molecular diffusivities in liquids

Table B .. 9

Tabu;Lated Parameters Using Short Time Equations

for Ethylene Glycol in Propylene Glycol

6 6 Run Frit Temp No. of DAB x 10 cfo x 10 No. No. oc. Data cm2/sec g-mo1e/liter

(3.10) (3. 9) (3 .10) (3. 9) (3. 9) (3.10) (3. 9) (3. 9) w w w w

* 55 3 25.0 5 12 l. 914 0.550 0.612 131.1 225 .. 2 194.2 ·J: * 56 3 25.0 s 9 0.543 0.152 0 .. 176 63.85 114.1 95 .. 75

61 6 25.0 6 11 0.781 0.537 0 • 58L~ 21.33 50.49 33.26

62 6 25.0 6 12 0.734 0.528 0.559 ;23. 33 55.28 39.65

67 3 30.0 6 12 0.770 0.634 0.650 18.73 28~70 24.07

68 3 30.0 6 12 0.813 0.620 0. 64-0 16.98 32.33 24.84

73 6 40.0 6 10 1.219 0.854 0.916 42.31 74.55 56.94

7L~ 6 40.0 6 10 1.173 0.836 0.891 42.35 71.76 56. 2l~

79 3 40.0 6 11 1.045 0.853 0.900 41.12 58.07 1+8. 26

85 6 50.0 5 5 1.480 1.529 1.494 7.518 21.31 7.102

86 6 50.0 5 5 1.494 1.537 1.50.9 8. 640 44.15 8.121

* Results were not accepted.

AAPD

(3 .10) (3. 9) w

8.47 11.8

10.6 16.6

3.28 8.79

4.47 7.17

5.88 4.86

6.02 7.42

8.13 7.94

6.85 7.34

2.49 4.42

1. 7l~ 3.64

1.09 2.48

(3 0 9) w

9.57

13.1

6.01

5.50

4.85

7.24

7.89

6.65

3.10

1.80

;1.25

0'> l.:>

Page 83: Determination of molecular diffusivities in liquids

Run Frit Temp

No. No. oc.

87 4 26.6

88 4- 26.6

93 1 30.0

94- 1 30.0

99 4- 39.9

100 4 39.9

Table B .10

Tabulated Parameters Using Short Time Equations

i2£ Cyclohexanol in Ethylene Glycol

6 6 No. of DAB x 10 cfo x 10

Data cm2/sec g-mole/liter (3.10) (3. 9) (3 .10) (3. 9) (3. 9) (3 .10) (3. 9) (3. 9)

w w w w

8 12 0.674 o. 749 0.735 31.94 26.60 28.4-8

8 12 0.728 0.763 0.764- 31.79 29.60 29 .. 78

6 12 0.952 0.871 0.889 44.64 47.48 46.03

6 11 0.969 0.853 0.884- 4-4-.4-1 4-9.84- 4-6.74-7 11 1.263 1.24-5 1.261 55.27 54-.4-7 54-.77

7 12 1.613 1.299 1.34-2 4-3.09 54-.30 50.'+6

(3.10) w

5.89

2.32

2.41

5.18 3.11

2.52

MPD

(3. 9) (3. 9) w

5.85 5.4-3

3.85 . 3.82

2.56 2.60

4-.51 4-.35 2.56 2.52

3.93 3.4-0

'-1 Q

Page 84: Determination of molecular diffusivities in liquids

Run Frit Temp

No. No. oc.

89 5 26.6

90 5 26.6

95 2 3Q.,O

96 2 30.0

101 5 39.9

102 5 39.9

Table B.ll

Tabulated Parameters Using Short Time Equation

for Cyclohexanol in Diethylene Glycol

No. of DAB x 10 6

Cfo X 10 6

Data cm2/~ec g-mole/liter (3.10) (3 0 9) (3 .10) (3. 9) (3. 9) (3.10) (3. 9) (3. 9)

w w w w

8 10 0.604 0.586 o. 603 32.68 34.21 32.27

8 10 0.621 0.616 0.629 25.69 26.16 24.83

6 12 0.744 0,631 0,649 19.43 23.99 22.04

6 12 0.841 0.621 0.658 16.84 26.59 21.92

7 11 1.250 1.079 1.102 91.72 97.85 96.31

7 11 1.229 1.073 1. 102 90.92 97.98 95.22

AAPD

(3 ~ 10) (3. 9) w

4.85 4.52

6.28 5.38

3,13 3.47

2.98 5.09

1.35 1.62

2.36 3.34

(3. 9) w

3.95

5. 32 .

2.73

4.40

1.64

3.33

-....,J )-'

Page 85: Determination of molecular diffusivities in liquids

'.I'able B.l2

Tabulated Parameters Using Short Time Equations

for Cyclohexanol in Propylene Glycol

Run Frit Temp No. of DAB x 10 6

Cfo X 10 6

No. No. 0 c. . Data cm2/sec g-mo1e/liter (3 .10) (3. 9) (3 .10) (3. 9) (3. 9) (3.10) (3. 9) (3. 9)

w w w w

* * * 91 3 26.6 8 12 0.501 0.357 0. 393. 11.47 23.18 16.32

92 3 26.6 8 8 0.183 0.180 0.181 6.322 62.13 62.67

97 3 30.0 6 13 0.463 0.390 o. 400 10.37 13.65 12.47

98 3 30.0 6 12 o. 498 0.395 0.408 7.320 12.58 10.73

103 3 39.9 7 12 0.794 0.695 o. 710 63~42 68.15 66.~0

lOI.J. 3 39.9 7 11 0.923 0.686 0.719 57.97 69.05 65.70

* Results were not accepted.

AAPD

(3 .10) (3. 9) w .

8.15 7.76

2.34 2.33

2.98 2.5 7

2.87 4.28

4.39 3.52 1.34 3 ~40

(3. 9) w

7.76

2.33

2. Lp

3g57

3.21 3.04

-..,J 1'\J

Page 86: Determination of molecular diffusivities in liquids

Run No~

* 51

* 52

57

58

63

64

69

70

75

76

81

Frit

No.

4-4-

1

1

4

4

1

1 4-

4 1

*

Table B.l3

Tabulated Parameters Using Long Time Equation with Calibrated Leff

for Ethylene Glycol in Ethylene Glycol

No. of Temp D X 106 6 Cfo X 10

oc o(

cm2/sec Data g-mole/liter

-(3. 8) (3. 7) (3. 8) (3. 7) (3. 8) (3. 7)

13 25.0 45.74- 4-5.64 2. 54-2 2.172 0.057 0.094-

13 25.0 ;' 42.34- 41.92 2.286 1.934 0.064- 0.14-7

18 25.0 25.11 25.00 1.053 1.105 0.038 . 0.049

18 25.0 25.59 25.52 1.109 1.183 0.036 0.044

15 30.0 23.16 23.18 1.123 1.185 0.046 0.060

15 30.0 24.30 24.36 1.254 1.337 0.031 0.043

12 40.0 29.92 30.07 1.991 2.262 0,087 0,082

12 40.0 28.69 28.79 1.802 2.014 0.083 0.081

18 4-0.0 24-.85 24-.92 1.576 l. 756 0.075 0.071

18 40.0 23.70 23.~5 1.510 1.601 0.059 0.066 * * * 7 so.o 32.90 24.98 4.138 4.138 0.034 0.034

Results were not accepted because of large deviation.

AAPD

-(3. 8) (3. 7)

9.04 14.8

9.76 14.3

2.11 2.88

1.53 1 .. 68

3.54 4.28

5.56 3.76

3.87 3.57

4.15 4.02

2. 4-3 2.19

1.53 1.83

2.79 18.0 *

" t..tJ

Page 87: Determination of molecular diffusivities in liquids

Run

No.

* 54

59

60

65

66

7.1

72

77

78

*

Frit

No.

5

2

2

5

5

2

2

5

5

Table B .14-

Tabulated Parameters Using Long Time Equation with Calibrated 1.eff

for Ethylene Glvcol .ill Diethylene Glycol

No. of Temp D X 106 6 Cfo X 10

oc ~ 2 Data em /sec g-mole/1iter

(3. 8) (3. 7) (3. 8) (3. 7) (3 •. 8) (3. 7)

14- 25.0 36.27 35.58 1.14-7 1.170 172.5 180.9

18 25.0 28.92 28.82 0.930 0.971 58.64 63.26

18 25.0 27.96 26.4-2 0.765 0.779 57.66 69.4-0

15 30.0 29.20 29.19 1.026 1.130 66.94 65.25

15 30.0 28.20 28.20 0.976 1.073 69.37 68.34

12 4-0.0 40.35 39.78 2. 248 2.644 94.38 81.39

12 40.0 38.73 38.96 1.973 2.265 104.4 98.33

18 40.0 33.38 33.51 1.807 2.111 121.4 104.8

18 40.0 33.41 33.62 1.853 2.232 118.9 95.84

Results were not accepted.

AAPD

-(3. 8)

12.5

1.82

3.18

4.78

3.14

3.30

4.17

3.56

3.75

(3. 7)

13.·2

2.13

3.53

4.52

3.00

1.68

3.38

2.78

2.24

'-I -1=

Page 88: Determination of molecular diffusivities in liquids

Table B.lS

Tabulated Parameters Using Long Time Equation with Calibrated ~ff

for Ethylene Glycol in Propylene Glycol

Run Frit No. of Temp 0 No. No. Data C

(3. 8)

ol.

(3. 7)

6 D X 10 2 em /sec

(3. 8) (3. 7)

6 Cfo X 10

g-mole/liter

(3.8) (3. 7)

AAPD

(3.8) (3. 7)

55 3 14- 25.0 36.4-8 36.88 1.216 1.4-03 225.2 218.5 . 10.8 10.4-

56 3 lr+ 25.0 68.37 67.79 1.092 1.158 114-.1 116.2 11.9 12.2

61 6 18 25.0 28.80 28.22 0.720 0.736 50.4-9 59.82 4-.88 5.78

62 6 18 25.0 27.16 25 .. 78 0.629 0.599 55.28 68.4-2 4-.11 5.01

67 3 13 30 .. 0 25.0'+ - 0.660 - 28.70 4-8. 65 4-.90

68 3 13 30.0 26.82 24-.03 0.730 0.618 32.33 50.91 6.92 7.4-9

73 6 12 40.0 30.81 30.96 1.367 1.525 74.55 72.59 5.78 5.65

74- 6 12 4-0.0 28.94- 28.24- 1.160 1.190 71.76 77.28 5.4-4- 5.82

79 3 19 4-0 .. 0 30.06 29.84- 1.238 1.309 58.08 65.18 2.30 2.82

* * * 85 6 5 50.0 35.93 24-.98 3.073 3.075 2.14-5 . 2.135 3.96 28.8

* * * 86 6 5 50.0 36.51 24-.98 3.175 3.175 4-.4-15 4-.4-15 2.63 29.5

* Results were not accepted. ......, IJl

Page 89: Determination of molecular diffusivities in liquids

Table B.l6

Tabulated Parameters Using ~on~ Time Eguation ~ Calibrated 1eff

for Cyclohexanol in Ethylene Glycol

Run Frit No. of Temp 0 No. No. Data C

87 4 14 26.6

88 4 14 26.6

93 1 15 30.0

94 1 15 30.0

99 4 15 39.9

100 4 15 39.9

*

(3 .• 8)

42.44

43.99

31.J.. 62

37.76

30.94

28.94

Results were not accepted.

o<

(3. 7)

42.55

44-.29

* 21.J..98

35.12

30.94

28.96

D X 106 2 em /sec

(3 .8) (3. 7)

2.294 2.546

2.558 2.942

1.618 1.168

1.897 1 .. 729

1.959 2.142

1.803 1o960

*

Cfo X 106

g-mole/1iter

(3 .8) (3. 7)

26.66 25.89

29.60 25.78

'-l7 .I.J.9 I.J.7.91.J.

49.86 51.16

55.46 56.10

*

54.30 56.14

MPD

(3 .. 9) (3. 7)

5.70 5.84

4.25 4.43

* I.J..02 20.6

4.18 4.20

1.95 1.98

2.66 2.86

'-1 en

Page 90: Determination of molecular diffusivities in liquids

Run FZ.lit No. Nq.

89 5

90 5

95 2

96 2

101 5

102 5

Table B.l7

Tabulated Parameters Using Long Time Equation with Calibrated 1eff

iQ£ Cyclohexanol ill Diethylene Glycol

No. of Temp D X 106 6 Cfo X 10

oc d.. 2 Data em /sec g-mo1e/1iter

-(3. 8) (3. 7) (3 .8) (3 '7) (3 .8) (3. 7)

14- 26.6 4-7.98 4-6.93 ' 2.158 2.179 34-.20 37.90

ll.J. 26.6 l.J.5.88 l.J.l. 92 2.001 1.683 26.15 34-.80

15 30.0 54-.63 55.86 3.135 3.657 23.99 22.71

15 30.,0 63.04- 6l.J..68 4-.823 5.33l.J. 26.59 21.09

.15 39.9 27.4-9 27.22 1.287 1.328 97.85 105.93

15 39 .. 9 29.82 29.72 1.511 1.612 97.98 102.72

Ml?D

(3. 8) (3. 7)

3.62 '+.26

5.35 5.26

2.73 . 2.l.J.O

3.85 2.59

2.35 2.08

2.82 2.87

..... .....

Page 91: Determination of molecular diffusivities in liquids

Rilll

No.

91

92

97

98

103

104·

Frit

No.

3

3

3

3

3

3

*

Table B.18

Tabulated Parameters Using Long Time Equation ~ Calibrated 1erf for C~clohexanol in Propylene Glycol

No. of Temp D X 106 cfo X 106

oc cl.. 2 Data em /sec g-mole/liter

(3 .. 8) (3. 7) (3. 8) (3 .7) (3.-8) (3. 7)

* * 23.17* 13 26.6 33.82 24-.98 0.583 0.583 23.17

12 26.6 38.20 24-. 98 * 0. 304- 0.304-* 62.14- 62.13 *

* * * 15 30.0 35.04- 24-.98 0.779 0.779 13.64- 13 .. 64-

15 30.0 37.07 59.10 0.865 2. 4-35 12.58 12.94-

15 39.9 36.43 3 6. 4-3 1.477 1.619 68.14- 68.12

15 39.9 36.76 36.76 1.512 1.675 69.04 67.4-8

Results were not accepted.

MPD

(3. 8) (3,. 7)

9.4-5 14-.5

8.34- 22.6

2. 4-8 22.8

3.4-lJ. 3.36

2.96 2.96

2.4-9 2.38

" (X)

Page 92: Determination of molecular diffusivities in liquids

Run No.

* 51

* 52

57

58

63

64

69 70

75

76

81

Table B.l9

Tabulated Parameters Using Long Time Equation with 1eff ~ Variable

for Ethylene Glycol in Ethylene Glycol

Frit No. of Temp D X 10 6 cfo X 106

oc Leff 2 No.· Data em /sec g-mole/liter

em

(3. 8) (3. 7) (3. 8) (3. 7) (3. 8) (3. 7)

4- 13 25.0 0.324- 0.324- 0.685 0.685 0.057 0.057

4- 13 25.0 0.339 0.327 0.751 0.651 0.064- 0.104-

1 18 25.0 0. 5 45 0.54-2 1.111 1.081 0.038 0 .. 04-3

1 18 25.0 0.536 0.532 1.128 1.095 0.036 0.04-l

4- 15 30.0 0.582 0.582 I. 4-3 7 1.380 0.046 0.051

lj. 15 30.0 o.sss o.sss 1.439 1.335 0.032 D. 043

1 12 40.0 0.459 0.454 1.475 1.4-75 0.087 0.083

1 12 40.0 0.502 0 .l~80 1.334 1.389 0.084 0.076

4 18 40.0 0.546 o. 54-3 1.715 1.678 0.075 0.071 Lj. 18 LJ.O. 0 0.560 0.568 1.816 1. 736 0.059 0.068

1 7 50.0 0.354- - 2.500 - 0.034 -

* Results were not accepted.

AAPD

(3. 8) (3. 7)

9.01 9.01

9.60 14-.2

2.13 2.02

1.56 1.18 3 o LJ.3 3.4-4

5.38 3.80

3.86 3.55

4-.80 4.07

2.4-9 2.19

1.58 1.87

9.78

-....J 1.0

Page 93: Determination of molecular diffusivities in liquids

Run Frit

No. No.

54 5

59 2

60 2

65 5

66 5

71 2

72 2

77 s 78 5

Table B.20

Tabulated Parameters Using Long Time Equation with Leff a Variable

for Ethylene Glycol in Diethylene §1ycol

No. of Temp D X 106 . 6 Cfo X 10

Data oc 1eff 2 g-mole/liter em /sec em

(3.8) (3. 7) (3. 8) (3. 7) (3. 8) (3. 7)

14 25.0 0.372 0.376 0.583 0.553 172.5 180.8

18 25.0 0.475 0.471 0.713 0.699 58.64- 59.95

18 25.0 0.4-91 0.4-93 o. 64-9 0.616 57.66 69.10

15 30.0 O.I.J.70 0. 4-66 . 0.791 0.786 66 .. 97 63.80

15 30.0 0.4-88 0.4-82 0.795 0.798 69 .. 37 66.26

12 30.0 o.31.J.6 0. 34-0 0.934- 0 .. 986 91.J..38 8l.I.J.2

12 40.0 0.352 0.351 0.882 0.887 104.4 89.57

18 40.0 0.409 0.404 1.061 1.105 121.4 105.8

18 I.J.O.O 0.410 0.402 1.099 1.165 118.9 96.09

MPD

(3. 8)

12 .. 6

1.77

3.24

4-.81

3.04-

3.23

4-.14-

3.58

3.74

(3. 7)

13.2

1.94

3.49 I.J..27

2.68

1.68

3.82

2.79

2.37

co 0

Page 94: Determination of molecular diffusivities in liquids

Run No.

55

* 56

61

62

67

68

73

74

79

85

86

Frit

No.

3

3

6

6

3

3

6

6

3

6

6

*

Table B. 21

Tabulated Parameters Using Long :J:ime Equation with Leff .!! Variable

for Ethylene Glycol in Propylene Glycol

No. of Temp D X 106 6 Cfo X 10

oc 1eff 2 Data em /sec g-mole/liter

em

(3 0 8) (3. 7) (3. 8) (3. 7) (3. 8) (3. 7)

14 25.0 0.362 0.366 0.620 0.611 225.2 218.7

14 25.0 0.324 0.32l~ 0.145 0.145 114.1 . 114.1

18 25.0 0.479 0.479 0.572 0. 5L~8 50.49 59.49

18 25.0 - 0.525 - 0.534 - 67.89

13 30.0 - 0.774 - 0.655 - 36.59

.13 30.0 o. 467 0.561 0.642 0.631 32.33 51.22

12 4-0.0 0. 4-05 0.4-23 0.968 0.952 74.55 80.57

12 40.0 - 0.479 - 0.883 - 76.60

19 40.0 o. 458 0.456 0.905 0.893 58.08 60.53

5 50.0 0.349 - L562 - 2.131 -5 so.o 0.34-9 - 1.565 - 1+.415 -

Results were not accepted.

AAPD

(3. 8). (3. 7)

10.8 10.4

15.0 10.9

4.92 5.73

- 4.96

- 4-.73

6.82 7.53

7. 34- 6.49

- 5.76

2.32 2. 4·8

9.75

9.28

00 I-'

Page 95: Determination of molecular diffusivities in liquids

Run

No.

87

88

93

9ft

99

100

*

Table B.22

Tabulated Parameters Using Long ~ Equation with Leff ~ Variable

for Cyclohexanol in Ethylene Glycol

Fl'it No. of Temp D X 106 cfo

6 X 10.

oc L f~ ·2; No. Data e r em sec g-mole/li tet• em

(3. 8) (3. 7) (3 0 8) (3. 7) (3.8) (3. 7)

It lit 26.6 0.330 0.320 0.801 0.821t 26.66 2ft. 32

4 14 26.6 0.325 0.325 0.822 0.822 29.60 29.60

* * 1 15 30.0 0.357 0.566 0.885 0.863 lf7.1t9 126.7

1 15 30.0 0.356 0. 31t3 0.875 0.869 lt9. 86 lt9.01t

4 15 39.9 0.444 0.439 1.350 1.334 55.46 54.96

It 15 39.9 O.lt74 o.LJ.69 1.427 1.398 Sit. 30 Sit. 56

Results we!'e not accepted.

MPD

-(3. 8) (3. 7)

11.0 6.23

10.1t8 3.99

* 7.79 25.5

8.79 lf.l9

1.96 1.96

2.61 2.70

CXl N

Page 96: Determination of molecular diffusivities in liquids

Run Frit

No. No.

89 5

90 5

95 2

96 2

101 5

102 5

Table B.23

Tabulated Parameters Using Long Time Equation with ~ff ~ Variable

for Cyclohexanol i~ Diethylene Glycol

No. of Temp D X 106 cfo X 106

oc Leff 2 Data em /sec g-mole/1iter

em . (3 .8) (3. 7) (3.8) (3. 7). (3 .8) (3. 7)

14- 26.6 0. 34-5 0.318 0.577 0.577 34-.20 34-.79

14- 26.6 0. 34-4- 0.335 0.597 0.581 26.15 29.98

15 30.0 0.332 0.332 0.657 0.657 23.99 23~99

15 30.0 0.333 0.333 0.638 0.638 26.59 . 26.59

15 39.9 0.4-99 0.4-97 1.132 1.080 97.85 103.8

15 39.9 0.462 0.4-58 1.112 1.101 97.98 99.98

AAPD

(3. 8)

9.36

9.19

9.4-7

9.96

2.4-0

2.88

(3. 7)

4-.69

5.66

2.97

4.30

2.01

2.76

00 UJ

Page 97: Determination of molecular diffusivities in liquids

Run No.

91

92

97

98

103

104

*

Frit

No.

3

3

3

3

3

3

Table B. 24-

Tabulated Parameters Using Long Time Equation with 1eff .§!.Variable.

fQ£. Cyclohexanol i£ Propylene Glycol

No. of Temp D x 106 cfo X 106

oc Leff 2 Data em /sec g-mole/liter

em

(3 .8) (3. 7) (3. 8) (3. 7) (3. 8) (3. 7)

* * 13 26.6 0.324 0.324 0.359 0.359 23.17 23.17

12 26.6 Oo325 0.325 0.146 0.146 6.213 6,213

15 30.0 0.320 - 0,413 - 13.64 -15 30.0 0.322 - 0.412 - 12.57 -15 39.9 0.375 0.372 0.736 0.725 68.14 6.755

15 39.9 0.373 0.369 o. 745 0.736 69.04 67.17

Results were not accepted

AAPD

(3. 8) (3. 7)

11.5 8.41

5. 73 13.1

10.4

10.5

2.97 2.86

2.50 2.37

CD +=

Page 98: Determination of molecular diffusivities in liquids

Table B.25

Computer Results of Run 1 Using Short Time Equations

RUN = 1 SOLUTE = 2 SOLVENT = 1 FRIT CODE = 1 TEMPERATURE = 25.0000 CALIBRATION THE FRIT KNOWN DIFFUSIVITY OF SOLUTE DF= 0.161 ·D-0~ INITIAL SOLUTE CONCE~ITRATION IN FRIT CO= 0.111 D-02 EQ. 3.10.DATA POINT FROM 3 TO 11 TOTAL POINTS= 9 EQ. 3.9 DATA POINT FROM 3 TO 11 TOTAL POINTS = 9

T (I) X(I) Y(I) ,EXP. CONC. SEC SQRT T G-MOL/LITER

10.20 3.19 0.2759D-05 27.00 5.20 0.36~7D-05 ~2.00 6. ~8 0.3256D-05

192.00 13.86 0.5980D-05 ~92.00 22.18 0.94~5D-05 840.00 28.98 0.1188D-05

1356.00 36.82 O.l479D-04 2028.00 45.03 O.l621D-OL~ 3246.00 56.97 0.2175D-04 ~146. 00 64.39 0. 2~86D-04 5142.00 71.71 0.2701D-O~ 604-2.00 77.73 0.2689D-04 7842.00 88.5G 0.3044D-04 8742.00 93.50 0.33SSD-04 9642.00 98.19 Q. 3421D-04

10542.00 102.67 0.3608D-04 11442.00 106.97 0.3784D-O~ 12444.00 111.55 0.3828D-04 63240.00 251.48 0.4834D-0~

CF (I) .,EQ. 3.10 G-MOL/LITER

0.3349D-05 0.606~D-05 o.9127n-os 0.1163D-04 0.1451D-04 0.1753D-04 0.2193D-04 0.2465D-04 0.2735D-04

MASS TRANSFER AREA (EQ. 3 .. 10) AT= O.l0983381D 02 (EQ. 3. 9) CONC. AT TIME EQUALS ZERO (EQ. 3 .10) CFO= 0.96505322D-06 (EQ.3.9) ABS. AVE. PERCENTAGE DEV. (EQ. 3 .10) A.A.P.D.= 0.18246713D 01 (EQ.3 ~9) STANDARD DEVIATION IN AT (EQ. 3 .10) STAR= 0.21972986D-02 (EQ. 3 .9)

CF (I) , EQ. 3. 9 G-MOL/LITER

0.3321D-05 0.6070D-OS 0.9160D-05 0.1167D-04 0.1~56D-04 0.1757D-04 0.2192D-O~ 0.2461D-04 0.2726D-04

0.11025715D 02 0.89730372D-06 co D.16289419D 01 lJ1

0. 42010415D-03

Page 99: Determination of molecular diffusivities in liquids

Table B.26

Computer Results of Run 1 Using Long Time Equation

RUN = 1 SOLUTE = 2 SOLVENT = 1 FRIT CODE = 1 TEMPERATURE = 25.0000 CALIBRATION, LONG DIFFUSION TIME EQUATION (EQ.3.8) FOR 2-VARIABLE SEARCH, (EQ.3·7) FOR 3-VARIABLE SEARCH DATA POINT FROM 3 TO 18 TOTAL POINTS = 16 DAB= 0.161 D-04 CO=O.lllD-02

T (I) SEC 10.20 27.00 42.00

192.00 492.00 840.00

1356.00 2028.00 32l~6.00

4146.00 5ll~2. 00 6042.00 7842.00 8742.00 9642.00

1054-2.00 11442.00 12444.00 63240.00

ALPHA= VF/VS· EFFE. TRANSFER LENGTH INITIAL CONC. IN BATH ABS. AVE. PER. DEV. FIRST EIGENVALUE B(N) VOLUME RATIO OF FLUID

X(I) Y(I) ,EXP. CONC. SQRT T G-MOL/LITER

3.19 5.20 6.48

13.86 22.18 28.98 36.82 45.03 56.97 6LJ..39 71.71 77.73 88.56 93.50 98.19

102.67 106.97 111.55 251.48

0.2759D-05 0.36LJ.7D-05 0.3256D-05 0.5980D-05 0. 94L~SD-05 O.l188D-04 0.1479D-04 0.1721D-04· 0.2175D-04 0. 24.S6D-04 0.2701D-04 0.2689D-04 0.3044D-04 0.3355D-04 0.3421D-04-0.3608D-04-o. 3 78Lm-04 0. 3828D-OLJ. 0.4834D-04

(EQ. 3. 8) (EQ. 3. 8) (EQ. 3. 8) (EQ: 3. 8) (EQ. 3. 8) (EQ. 3. 8)

A= 0.24010540D 02 L= 0.56460397D 00

CFO= 0.99657020D-06 A.A.P.D.= 0.35012946D 01

B(l)= O.l5871250D 01 VF= 0.29875696D 03

CF(I) ,EQ.3.8 G-MOL/LITER

0.2976D-05 0.5692D-05 0.8744D-05 O.ll22D-04 O.l408D-04 O.l706D-04 0.2137D-04 0. 2402D-04 0.2658D-04 0.2861D-04 0.3204-D-04 0. 331+8D-04 0.34-76D-04-0.3590D-04-0.3692D-04 D.3793D-04

(EQ. 3. 7) (EQ. 3. 7) (EQ. 3. 7) (EQ. 3. 7) (EQ. 3. 7) (EQ. 3. 7)

CF(I) ,EQ.3. 7 G-MOL/LITER

0.3838D-05 0.6407D-05 0.9295D-05 O.ll64D-04 O.l434D-04 0.1716D-04 0.2125D-04 0.2378D-04 D.2625D-04 D.2826D-04 0.3176D-04 0. 33 29D-04 0. 3 469D-Ot~ 0.3598D-04-D.3715D-04 D.3835D-04

0. 22065416D 02 0.64904295D 00 0.21368481D-05 0.34517091D 01 O.l5871250D 01 0.31561508D 03

00 0'1

Page 100: Determination of molecular diffusivities in liquids

Table B.27

Computer Results of Run l~ Using Short Time Equations

RUN = 76 SOLUTE = 3 SOLVENT = 3 FRIT CODE = ~ TEMPERATURE = 40.0000 CALCULATION THE MOLECULAR DIFFUSIVITIES EQ. 3.10 DATA POINT FROM 1 TO 6 TOTAL POINTS = 6 EQ. 3.9 DATA POINT FRQ~ 1 TO 1~ TOTAL POINTS= 14 AT IN EQ.· 3 •. 10 11.019 AT IN EQ 3.9 10.970 CO= 0.360D-04

T (I) X(I) Y (I) ,EXP. CONC. CF (I) ,EQ. 3.10 CF (I) ,EQ. 3~ 9 SEC SQRT T G-MOL/LITER G-HOL/LITER G-MOL/LITER

72.00 8.49 0.7923D-07 0.8152D-07 0.8489D-07 906.00 30.10 0.1750D-06 O.l660D-06 O.l679D-06

4254-.00 ·65. 22 0.2986D-06 0.3033D-06 0.3023D-06 6513.00 80.70 O. 3534-D-06 0.3638D-06 0.3613D-06 7908.00 88.93 0.4018D-06 0.3960D-06 0.3926D-06 9858.00 99.29 D.4-4-02D-06 0.4-365D-06 0.4-319D-06

18288.00 135.23 0.5884-D-06 0.5678D-06 22104.00 148.67 0.6239D-06 0. 6184-D-06 26508.00 162.81 0.6828D-06 0.6715D-06 61863.00 24-8. 72 0.1006D-05 0.9916D-06 734-3 7. 00 270.99 0.1047D-05 O.J.073D-05 80280.00 283.3!+ 0.1108D-05 o.1119n~o5

90219.00 300.36 0.1184D-05 O.ll81D-05 95364-.00 308.81 O.l190D-05 0.1212D-05 97308.00 311.94 0.1185D-05

106794.00 326.79 0.1217D-05 117606.00 34-2.94- 0.124-2D-05 144294.00 379.86 0.1365D-05 168738.00 410.78 0.1359D-05

l'10LECULAR DIFFUSIVITY (EQ. 3 .10) D= 0.16168768D-05 (EQ. 3 .9) 0 .1612214-0D-05 CONC. AT TIME EQUALS ZERO (EQ.3 .10) CPO= 0.48347695D-07 (EQ. 3 .9) 0.521954-4-4D-07 ABS. AVE. PERCENTAGE DEV. (EQ. 3 .10) A.A.P.D.= 0.24-809105D 01 (EQ. 3 .9) 0.22853063D 01 STANDARD DEVIATION IN DAB (EQ. 3 .10) STAR= 0.12321053D-09 (EQ. 3 .9) O.ll503164D-10

co -.....

Page 101: Determination of molecular diffusivities in liquids

Table B.28

Computer Results of Run 1.§_ Using Long Time Equation

RUN = 7 6 SOLUTE = 3 SOLVENT = 3 FRI'l' CODE = 4-TEMPERATURE = 40.0000

. CALCULATION, LONG DIFFUSION TIME EQUATION (EQ.3.8) FOR 2-VARIABLE SEARCH, (EQ. 3.7) FOR 3-VARIABLE SEARCH

DATA POINT FROM 1 TO 18 TOTAL POINTS = 18 2-VARIABLE SEARCH L= 0.531 3-VARIABTJE SEARCH L= 0.556

T(I) X(I) Y(I) ,EXP. CONC. CF(I) ,EQ.3.8

CO= 0.360D-04-

CF (I) ,EQ. 3. 7 G-MOL/LITER SEC SQRT T G-MOL/DITER G-MOL/LITER

72.00 906.00

4-254.00 6513.00 7908.00 9858.00

18288.00 22l0L~. 00 26508.00 618,63.00 73L~37.00

80280.00 90219.00 95364.00 97308.00

10679lf-. 00 117606.00 14-l~294-. 00 168738.00

8. 49 30.10 65.22' 80.70 88.93 99.29

135.23 148.67 162.81 248.72 270.99 283.34 300.36 308.81 311.94-326.79 34-2.94-379.86 4-10.78

ALPHA = VF/VS MOLECULAR DIFFUSIVITY INITIAL CONC. IN BATH ABS. AVE. PER. DEV. FIRST EIGENVALUE B (N)

(EQ. 3.8) (EQ. 3. 8) (EQ. 3. 8) (EQ. 3. 8) (EQ. 3.8)

0.7923D-07 0.1750D-06 0.2986D-06 0.353lf-D-06 0.4018D-06 0.4402D-06 0.4-884D-06 0.6239D-06 0.6828D-06 0.1006D-OS O.l047D-05 O.ll08D-05 O.ll84D-05 O.ll90D-05 O.ll85D-05 O.l217D-05 O.l242D-05 0.1365D-05 0.1359D-05

A= 0.23703969D 02 DAB= 0.15100674-D-05 CFO= 0.59851930D-07

A.A.P.D .• =:= O.l5341391D 01 B(l)= O.l5871250D 01

0.7927D-07 0.16li-5D-06 0.3023D-06 0.3628D-06 0.3949D-06 0.4-3l~3D-06 0. S 74-BD-06 0.6269D-06 0.6815D-06 0.1001D-05 0.1075D-05 O.ll14D-05 o.ll6lm-os 0.1187D-05 0.1196D-OS 0.1234-D-05 0.1272D-05 0.134-SD-05

(EQ. 3. 7) (EQ. 3. 7) (EQ. 3. 7) (EQ. 3. 7) (EQ. 3. 7)

0.8540D-07 0.1698D-06 0.3062D-06 0.3661D-06 0.3978D-06 044-378D-06 0.5759D-06 0.6275D-06 0.6815D-06 0.9991D-06 O.l073D-05 O.lll2D-05 041163D-OS 0.1187D-05 0.1195D-05 0.123 4-D-05 0.1273D-05 O.l349D-05

0.23553733D 02 0.16019585D-05 0.6651854-?D-07 O.l8337062D 01 O.l5871250D 01

00 00

Page 102: Determination of molecular diffusivities in liquids

APPENDIX C

Prediction of Molecular Diffusivities Using

Correlation Equations

This appendix presents sample calculations and their results

o'f the predicted values of the molecular diffusivities for the

various methods studied in this work. The data~ taken from

literature or measured in this laboratory, required for these

calculations are included in this appendix.

89

Page 103: Determination of molecular diffusivities in liquids

Table C.l

Viscosity and Molal Volume Dataa

Temp. Cyclohexanol Ethylene glycol Diethylene Pl"opylene oc glycol glycol

fl. v p. ·v f-l. v p v cp m1/mo1e cp ml/mo1e cp m1/mo1e cp m1/mo1e

20.0 70.00 104.07 20.61 55.70 35.03 94.95 58.86 73.31

25.0 55.00 105.22 16.60 55.87 27.16 95.26 43.36 73.56

30.0 4-2.00 106.38 13.56 56.04 21.61 95.56 32.62 73.84

40.0 26.00 107.26 9. 41 56. '+0 14.35 96.16 19.56 74.38

. 50.0 16.00 108.56 6.77 56.77 10.02 96.81 12.40 74.94

~iscosity and molal volume data for glycols were measured in this laboratory by Mr .. James Moore. For cyclohexanol the viscosity and density were taken fr.orri Perry's Handbook of Chemical Engineering, '+th ed., p. 3-196 (1963) and Timmermans' Handbook of Physico-Chemical Tables, p. '+91 (1950). The values of molal volume were calculated from density data.

1.0 0

Page 104: Determination of molecular diffusivities in liquids

Compound

Cyclo-

b Tb oc

hexanol 161.1 (100.16) a Diethylene glycol 2~5.0 (106.12) Ethylene glycol 198.0 (62.07) Propylene glycol 189.0 (76.10)

Table c. 2

Heat of Vaporization Data

vc ml/mole

Homomorph Tb compound

methyl-121.9 cyclo­

hexanol

112.~ propyl-ether

66.6 Butane

88.8 Pentane

oc

100.4

91.0

-o.5

36.0

* 6.H va.p Al-I vap

Kcal/mole Kcal/mole 1 2 1 2

9.03 - 7.66

10.96 14.40 7.45 7.58

9.88 12.58 5.42 5.35

9.67 12.90 6.22 5.90

aMolecular weight of compound.

.6Hvap.x-H AH ap V.

1 2 3

0.152 - 0.575

0.320 0.481 0.443

0.451 0.575 0.363

0.356 0.543 . 0.409

bNormal boiling points data were taken from Weaster's Handbook of Chemistry and Physics. P. C-271, C-288, C-320, C-511, C-268, C-449, C-318, and C-216 (Ref. 13).

~olal volumes at normal boiling point were estimated by using the method outlined in the book by Reid and Sherwood (Ref. 9) and Pigford and Sherwood (Ref. 10).

dHeat of vaporization "1" were calculated by using Kistiakowsky' s Equation (C. 2f) (see Appendix C.3), "2n from Bondi and Simkin's Table (Ref. 1), 11 311 from Mitchell's Ph.D. Thesis (Ref. 5).

1.0 ......

Page 105: Determination of molecular diffusivities in liquids

92

Table C.3

Free Energy of Activation of Diffusion Process -- - - ==== =-=-==

Solute Solvent Temp AFD,AB Kcal/mole oc

J

A B

(1) (2)

ethylene ethylene 25.0 4-.85 4.63 glycol glycol 30.0 4-.85 4-.59

4-0.0 4.82 4-.52 50.0 4-.80 4. 47

E'thylene diethylene 25.0 5.24- 5.26 glycol glycol 30.0 5.22 5.21

40.0 5.20 5.14-50.0 5.19

ethylene propylene 25.0 s. 4-5 5.36 glycol glycol 30.0 5.4-7 5.28

4-0.0 5. 4-7 5.15 50.0 5.19 5.04

* cyclo- ethylene 26.6 5.09 4.55 hexanol glycol 30.0 5.06 4.51

40.0 4-.98 4.45

* cyclo- diethylene 26.6 5.38 5.20 hexanol glycol 30.0 5.38 5.16

40.0 5.27 5.09

* cyclo- propylene 26.6 5.75 5.29 hexanol glycol 30.0 5.75 5.22

40.0 5.61 5.09

Notice: A F D ,AB (1) were taken directly from Mitchell 1 s (5) Thesis.

AFD AB (2) were calculated in this work using f = 0.99 in ' Equation (C.3b). (see Appendix C.3).

' 1 * 11 means 0

thatvalues obtained at run temperature 25.0 C.

Page 106: Determination of molecular diffusivities in liquids

C.l Calculation of Molecular Diffusion Coefficients Using

Wilke-Chang Correlation

The empirical form suggested by Wilke and Chang(l2)is

93

= 7.'+ x l0-8 ('fB~)%T t..(B(V~0.6

(C.la)

where DAB = mutual diffusion of solute A in solvent B

2 at very low dilute concentration, em /sec

~ = molecular weight of solvent

T = temperature, °K

~B =viscosity of solution (solvent), centipoises

VA = molal volume of the solute at its normal boiling

point, cm3/g-rnole

lfB = n association parametersn of solvent, having values

of 2.6 for water, 1.9 for methanol, 1.5 for ethanol,

and 1.0 for unassociated solvents.

A. Sample Calculation

Syste~: Diffusion of cyclohexanol into diethylene glycol <

at 25°C (DAB = 0.610 x 105 cm2/sec at 25.6°C) · ,exp. 3 Data VA = 121.9 em /g-mole

M:s = 105.12

f).B = 27.16 cp

T = 298 OK

o/B = two limiting cases r= 1.0 and 2.5 are

interested in this study.

Page 107: Determination of molecular diffusivities in liquids

If: lpB = 1. 0

Then:

·. 8 ~ . D = JZ.4 X 10- ) (1.0 X 106.12) 2 (298)

AB (27 .16) (121.9) 0• 6

= -6 2 0.468 x 10 em /sec

If: lf>B = 2.6

Then:

DAB = (7.4 X 10-8) (2.6 X 106.12)~ (298)

(27 .16) (121. 9) 0• 6

= 0.755 -6 2 x 10 em /sec

Similarly, one can predict the molecular diffusivities by using

this correlation equation to other solute-solvent systems which

are of interest.

B. Table of Results

The predicted molecular diffusivities of highly viscous

solute-solvent systems by using Equation (C.la) are included in

Table C.4.

C. 2 Calculation of 1'1olecular Diffusion Coefficients Using

Modified Eyring Rate Equation

Gainer and Metzner (3) developed a relation for predicting

diffusivities in liquid systems by considering the energy barriers

which a diffusion molecule encounters. They have also shown the

Page 108: Determination of molecular diffusivities in liquids

95

Table C.LJ.

Predicted Molecular Diffusivities Using

Wilke-Chang Correction Equation

J).B D X 106 D X 106 cp we exp 2

Solute Solvent Temp Viscos- cm2/sec em /sec A B oc ity <fB=l. 0 LfB=2. 6 (3. 9) (3. 9)

w

ethylene ethylene a 25.0 16.60 0.84-2 1.385 1.040 1.131 glycol glycol 30.0 13.56 1.048 1.691 1.278 1.330

LJ.O.O 9.14- 1.560 2.516 1. 4-09 1.516 50.0 6.77 2.237 3. 607 2. 4-16 2.4-91

ethylene diethylene 25.0 27.16 0.673 1.085 o. 614- 0.664-glycol glycol 30.0 21.61 0.860 1.387 0.720 0.763

LJ.O.O 14.4-0 1.338 2.157 0.852 0.913 . 50.0 10.03 1. 977 3.188

ethylene propylene 25.0 4-3.37 0.357 0.575 0.519 0.585 30.0 32.63 0.482 0.778 0.627 o. 64-5 4-0.0 19.56 0.831 1.341 0.847 0.902 50.0 12.4-1 1.353 2.182 1.530 1.502

AAPD (1) 17.97 54-. t~S AAPD (2) 17.65 62.39 cyc1o- ethylene 25.0 16.60 0.586 * * 0.94-5 0.755 0.7'.J.9 hexanol glycol 30.0 13.56 0.729 1.176 0.826 0.886

4-0.9 9. LJ.l 1.086 1.751 1.272 1.301 50.0 6.77 1.556 2.510

cyc1o- diethylene 25.0 27.16 0.468 0. 755 0.601 * * o. 616 hexanol glycol 30.0 21.61 0.598 0.965 0.626 0.653

LJ.O.O 14-.36 0.930 1.501 1.076 1.102 50 .. 0 10.03 1.375 2.221

cyc1o- propylene 25.0 ·43 .37 0.248 0.4-00 0.180 * * 0.181 hexanol glycol 30.0 32.63 0.335 0.54-1 0.392 0. 4-04

4-0.0 19.56 0.578 0.933 0.692 0. 714-50.0 12.4-1 0.94-1 1.518

AAPD (1) 19.67 62.73 AAPD (2) 17.16 4-5.95

Notice: AAPD (1) is the absolute average percent deviation of D from D with weighting factor (w) for every 3 systems, aj:ia AAPD (2)ef~om D without weighting factor. exp

*values obtained at run temperature 26.6°C.

Page 109: Determination of molecular diffusivities in liquids

96

equations to estimate the energy barriers from a knowledge of den-

sity, viscosity, and heat of vaporization of the fluid.

They star·ting with the Eyring absolute rate theory in the

form,

kT ( N Jl/3 ( E p. B - ED AB) DAB = ~AJJ.B VB exp \. ' RT ' (C.2a)

where E fl. can be estimated by the equation

(C.2b)

and (E~,B - ED,AB) can be estimated by the equation

E/1,B - ISJ,AB = Ei,B - E ~:){}~: E~2A-H :: E"'zB-H;J

(C.2c)

The ratio of the activation energy due to hydrogen bonding to the

total activation energy is assumed to be related to the heat of

vaporization by the following ratio

E .AH · 11 2 A-H = vap aA-H E AH p., A vap, A

The intermole~~ar

v 1/3

rAA =(NA)

spacing can be calculated as:

v 1/3

; rBB =( NB)

(C. 2d)

(C. 2e)

Page 110: Determination of molecular diffusivities in liquids

97

In this study, a method for estimating the heat of vaporiza­

tion is based upon the equation developed by Kistiakowsky(ll)which

is

aH ~~p = 8.75.+ 1.987 In Tb

D

{C. 2f)

The internal energy of vaporization at normal boiling point (Tb)

can be estimated from Tourton's rule~l)

(C. 2g)

~ , a lattice parameter, is estimated from self-diffusion data,

otherwise, for most liquid 5 = 6 can be used(4 , 3) or s = 8 for

glycols (3).

(5) oHvap A-H . Mitchell has given ratios of AH, for h~ghly viscous

vap,A sol vents (see 'fable C .1) and they were used in this study as well

as the values estimated from Equation (C.2f) and from Bondi and

Simkin 1 s Tables 6 and 7 (l).

A. Sample calculation

System: of cyclohexanol into ethylene glycol Diffusion

at 25°C -6 2 0

(D = 0. 744 x 10 em /sec at 26.6 C) AB,exp

Data

Solute cyclohexanol 0 Tb = 161.1 C

Homomorph: methyl-cyclohexane 0 Tb = 100.4 C

Solvent ethylene glycol Tb = 198.0°C

Homomorph: butane 0 Tb = -0.500 c

Page 111: Determination of molecular diffusivities in liquids

P.A = 55.0 cp jJ.B = 16.60 cp

v l/3 r -( A) = 5.59 x 10-8cm = 5.59 X AA-N

rBB --( NVB)1/3 = ~~.52 x 10-8cm = 4-.52 ~

* Then: estimate AHvap and A Hvap from Equation (C.2f)

Therefore,

H va.J2 = 8.75 + 1.987 1n Tb Tb

Hvap (A) = 9.03 Kcal/rnole .

* * Kcal/rnole H (A) = 7.66 vap

H (B) vap = 9.88 Kcal/mole

* * Kcal/rnole H (B ) = 5. 4-2 vap

heat of vaporization ratios can be

~=Va]2,A-H = 9.03 9 ~0~.66 = O.l52 vap,A

AH ' .6.H vaE ,B-H = 9. 88 9~ 8~. 4-2 = O. 4-S1

vap,B

calculated as

98

Page 112: Determination of molecular diffusivities in liquids

The internal energy of vaporization can be estimated from

Equation (C.2g), then

~ E _ = 8.108 . Kcal/mole vap.,A

6.E = 8. 797 Kcal/mo1e vap,B

Apply Equation (C. 2b)

E fA, A = 1. 987 ln 0.55 (105.22) 213 (81.08)

= 4-428.7 cal/ mole

Similarly we obtain

I +· .1. •

Then:

E )1., B = 3659.5 cal/mole

E }J., A-H =

4H vap,A-H

.6Hvap,A E}-<,A

EJ.I,A-H = (0.152)(4428.7) = 673.1 cal/rnole

E = (0.451) (3659.5) = 1650o4 cal/mole P,B-H

99

Page 113: Determination of molecular diffusivities in liquids

100

Therefore:

E~,A-D = Ef,A EM,A-H = 4428.7- 673.1 = 3755.6cal/mole

E,l.(,B-D = Ef,B - Ef,B-H == 3659.5 - 1650.4- = 2009.1 cal/mole

Using Equation (C. 2c) to calculate the value of (E).). ,B -ED ,AB) ,

if 5 A = SB = 8. 0

E -E == 3659.5 _ _El S 5.59 673.1 4.52 1650:-Lj: ;..t , B D ,AB 2 8 { 5. 05 2 5. 05 2

)(5.52_)12 + 5.05

3755 .. 6 (4.52)12 2 . \5.05

== 20.80 cal/mole

Us:L'1g Equation (C. 2a) to calculate the diffusivity

1/3

(l. 38 X lo-16) (298) ( 6. 023 X 1023) (8) (D. 2716) 95.26

20.80 -6 2 1 _987 x 298 = 0.708 x 10 ern /sec

If 4 A = 5 B == 6.0, similarly

1 -6 2 DAB = 0. 943 x 10 em /sec

exp

Mitchell(5)used Bondi and Simkin suggested methods of calcu-

lation of heat of vaporization using atmospheric boiling point and

critical temperature(l)and estimated the heat of vaporization AH A H

ratioes vap, - for cyclohexanol and ethylene glycol as 0.575 .t::.H vap,A

and 0.363, respectively (see Table C.2). It can be seen that

Page 114: Determination of molecular diffusivities in liquids

101

Mitchc:ll's values are not in agreement with those calculated using

Kistiakowsky's equation. However, Mitchell calculated ratios are

also used in the calculations. The results are:

if S A = S B = 8.0

if ~A= SB = 6.0

Bondi and Simkin(l)have shown tables of the values of heat of

vaporization of various compounds and their homomorph. These

also were used in prediction of diffusivities. The diffusivities

predicted by using these values are defined as DAB 3 and included

in Table C.5. Since heat of vaporization data for cyclohexanol

and its homomorph are not reported by Bondi and Simkin, calcula-

tions are not performed for·systems using cyclohexanol as the

solute.

Gainer and Metz::1er reported that 5 = 8.0 for glycols may be

not true. It is fmmd in this work, that 5 = 6. 0 predicted better

results than s = 8. 0 by the three different approaches described

above, except the systems using Kistiakowsky's equation to calcu-

2 late the heat of vaporization of cyclohexanol (see D , cyclohexanol

as the solute in Table C.S). For this exception, s = 8.0 predicted

better results than s=6.0. The reason may be that

Kistiakowsky 1 s equation fails to predict accurately the heat of

vaporization of cyclohexanol. This may lead to the large differ-

ence of Hvap,A-H H vap,A

of cyclohexanol between the Mitchell 1 s value

Page 115: Determination of molecular diffusivities in liquids

Solute

A

ethylene glycol

ethylene glycol

ethylene glycol

AAPD (1) AAPD (2)

cycle- . hexanol

cyclo­hexanol

cyclo­hexanol

AAPD (1) AAPD (2)

Table C .. 5

Predicted Molecular Diffusivities Using

Gainer & Metzner Suggested Equation

102

Sol vent ' Temp oc

5 2 DAB.x 10 , em /sec

D2 nl

a

B ~ = 8 ~ = 6 ~ = 8 s = 6 ~= 8 ~= 6

ethyleneb glycol

diethylene glycol

propylene glycol

25.0 0.683 30.0 0.850 4-0.01.252 50.0 1.805

25.0 0.4-62 30.0 0.584-4-0.0 0.889 50.0 1.29'+

0.910 1.13'+ 1.683 2.'+08

0.616 0.779 1.182 1. 722

25.0 0.321 0.4-82 30.0 0.4-23 0.562 '+0.0 0.699. 0.930 50.0.1.096 1.4-12

27.03 11.66 24-.05 13.17

ethylene glycol

25.0 0.613 . 30.0 o. 770

4-0.0 1.159 50.0 1.699

0.815 1.025 1. 5'+1 2. 2'+5

diethylene glycol

propylene glycol

25.0 0.310 30.0 0.4-00 4-0.'0 o. 629 50.0 0.95'+

25.0 0.2'+'+ 30.0 0.328 4.0.0 0.555 50.0 0.903

27.21 26.23

o. '+65 0~535 o. 84-0 1.271

0.325 o. 4-37 o. 740 1.205 22.30 22.89

. 0. 683 0.850 1.262 1.806

0.'+72 0.569 0.906 1.316

0.910 1.134-1. 683 2. '+08

0.628 0.794 1.208 1.518

0.324- 0.432 0.4-28 0.670 0.706 0.94-1 1.106 1.54-8 26.65 11.88 23.68 12.13

o. 708 o. 94-3 0.885 1.179 1.320 1. 760 1.917 2.530

0.324- 0.4-32 0.416 0 .. 564-0.654- 0.873 0.989 1.320

0.262 0.351 0 .. 591 0.957 22 .. 94-22.4-6

0.34-9 0.468 0.789 1.269 30.85 31.4-2

0.683 0.850 1.262 1.806

0.4-56 0.567 0.879 1.279

0.910 1.134-1.683 2.4-09

0.608 0.768 1.172 1.705

0.318 0.4-24-0.4-20 0.560 0.694- 0.925 1.088 1.4-51 27.67 12.10 24-.4-7 12.77

aThe difference in D1 , D2 , and n3 is that various sources of heat of vaporization of compounds; therefore, different values of 1 ( Hvap x-HI Hvap) were used in calculations (see Table C.2). D are the vaiues using Kistiakowskyr s equation, D2 from Mitchell's ratio, and n3 from Bondi-Simkin's Tables.

bSelf-diffusion coefficient.

Page 116: Determination of molecular diffusivities in liquids

103

(0.575) and ·the value from Kistiakowsky's equation (0.152). For

an over-all observation for highly viscous systems studied in

this work, using Equation (C.2a) with s = 6.0 and heat of vaporiza-

tion data calculated by Mitchell (see Table C.2) from Bondi and

Simkin T s suggested method using critical· properties of solute

and solvent(l)predicted better results than the heat of vaporiza-

tion data calculated from KistiakowskyTs equation.

C.3 Calculation of Molecular Diffusion Coefficients Using

Free En~ of Activation

Mitchell(4)suggested a correlation for diffusion coefficients

by using Free Energy of Activation as follows:

'2" v 2/3 kT ( J B)

DAB = 5 h N exp - AFD,AB

RT (C. 3a)

where ~FD AB =Free energy of activation in the diffusion process. ,

A. Sample Calculation

System: Diffusion of ethylene glycol in diethylene glycol

at 25°C (D = 0.658 x 10~ 6 cm2/sec) exp

Data A FD AB = 5. 2!.J. Kcal/mole (see Table C.3) ' 3

VB = 95.26 em /rnolr (see Table C.l)

The geometric parameter may be assumed that$ = 6

for most liquids or ~ = 8 for glycol (see Reference

2, 4, 7). These two values will be studied in this

work.

Page 117: Determination of molecular diffusivities in liquids

If S = 6.0

= (1.38 X 10-16) (273 + 25)

(6) (6.625 X 10-27)

2/3

[ 2112 (95. 26) J l -524-0 • · • exp B.023 X 1023 1.987 X 288]

If S = 8.0

104-

The free energy of activation may be calculated from the

following equations:

jJ. VBJ2 LlF )..{ ,B = RT ln hN

(C.3b)

(C.3c)

It was assumed (S) that A F,ux is equal to A FDXX for both the

solute and solvent; therefore A FDAA and A FDBB can be calculated

from Equation (C.3c). The ratio of the enthalpy as in Appendix

C. 2 is again used to evaluate the part of ~ F DXX due to hydrogen

Page 118: Determination of molecular diffusivities in liquids

105

bonding. Thus

= AHvap,X-H AFD!XX AH

vap,X (C. 3d)

Again

(C.3e)

when using Equations (C.3a) and (C.3b) for the calculation of the

molecular diffusivities, the two factors f and 5 must be known.

Because little available data can be used~ various values of f and

S are tested in this study •. The results are included in Figures

7 and 8, and Table C.6. These results were discussed in Section

5.3.

C.4- Self-Diffusion Coefficient Calculation for Ethylene Glycol

The self-diffusion coefficient (DAA) for ethylene glycol at

various temperatures was estimated using the following mutual

diffusion coefficient (DAB) correlations: Wilke-Chang (llJ) ~

Gainer and Metzner (3) ~ and Mitchell (S). The results from these

three methods were included in Table C-~~ C.5, and C.6. However,

Nagarajan, Ryan, and Shemilt(8)show an equation for correlation

of seif-diffusion coefficient. This can be represented by the

following equation:

{C.I.f.a)

where p is the liquid viscosity in poises.

Page 119: Determination of molecular diffusivities in liquids

106

120

o~= 8

~ o~= 7 ~

..6 ;= 6 n

Wilke-c: 100 0 Chang •r-i -1-l (tpB =LO) rd •r-i !> Wilke-Q)

'lj Chang -1-l 80 c rB=2. 6) c: Q) C)

H Q)

Pi Q)

.j..J ;:j

60 rl 0 rJ)

~ Q)

bO res H Q)

!> 40 res

20

0.94 0.96 0.98 LOO

f

Fig. 7. Average absolute percent deviation of the pre­dicted molecular diffusivities for 2 systems (ethylene glycol as the solute) from the ex.peri­

mental values of Equation (3. 9) with weighting factor versus f and 5 .

Page 120: Determination of molecular diffusivities in liquids

107

l20

o~= 8

Q os= P-1 7

~ lOO ~;= 6 ... Wilke-Chang s::

0 --- (tpB = 1.0) •r-1 .j..l ctl Wilke-Chang •r-1 :> (t.pB =2. 6) Q)

"d 80 .j..l s:: Q) C) ~ Q)

Pr Q)

.j..l 60 .=!

0 0)

~ Q)

bO r:d ~ 4-0 Q)

:> ctl

20 --------·

0

0.94- 0.96 0.98 1.00

f

Fig. ·8. Average absolute percent deviation of the predicted molecular diffusivities for 3 systems (cyclohexanol as the solute) from the experimental values of Equation (3.9) with weighting factor versus f and;.

Page 121: Determination of molecular diffusivities in liquids

108

Table C.6

Predicted Molecular Diffusivities Using

F~ Energy of Activation

Solute Solvent Temp DAB x 106, 2 em /sec a

A B oc fAB D1 D2 D

~ cp (Eq. 3. 9)

s= 6 ~= 8 ~=6 ; = 8 w

ethylene ethyleneb 25.0 16.60 o. 7'+0 0.555 1.075 0.806 1.131 glycol glycol 30.0 13.56 0.863 0.674- 1.328 o. 996 1.330

4-0.0 9.14 1.216 0.912 1.94-9 1.4-61 1.516 50.0 6.77 1.652 1.239 2.758 2.069 2.491

ethylene diethylene 25.0 27.16 0.546 o.ruo 0.528 0.396 0.664-glycol glycol 30.0 21.61 0.666 0.4-99 0.607 0.502 0.763

40.0 14.4-0 o. 94-2 0.706 1.029 0.772 0.913

ethylene propylene· 25.0 4-3.37 0.322 0.242 0.373 0.279 0.585 glycol glycol 30.0 32.63 0.370 0.278 0.4-99 0.374- o. 64-5

4-0.0 19.56 0.514- 0.385 0.84-6 0.635 0.902 50.0 12.1+1 0.733 o .sso_ 1.357 1.018 1.502

AAPD (1) 29.15 46.16 15.86 29.21 AAPD (2) 26.88 4-2.67 15.04- 25.93

* cyclo- ethylene 25.0 16 .. 60 0.519 0.389 1.216 0.912 0.749 hexanol glycol 30.0 13.56 0.609 0. 456 1.500 1.125 0.886

40.0 9.14 0.940 0.705 2.190 1.64-2 1.301

cyclo- diethylene 25.0 27.16 o. 4-55 0.341 * 0.579 o. 434- 0.616 hexanol glycol 30.0 21.61 0.511 0.383 0.734- 0.551 0.653

40.0 14.40 0.841 0.631 ·1.123 0.84-2 1.102 * cycle- propylene 25.0 43.37 0.205 0.154 o.rn8 0.313 0.181

hexanol glycol 30 .. 0 32.63 0.244- 0.183 0.558 0.419 0.404 4-0.0 19.56 0.4-10 0.308 0.941 0.705 a. 714

AAPD (1) 28.25 45.77 46.97 24.62 AAPD (2) 27.07 43.55 49.31 25.01

a Dl, are calculated by using experimental values of free energy of activation reported by Mitchell (see Table C.3). n2 are calculated by using f = 0. 99 in Equation (C. 3b). The calculated Fn ABare listed in Table C.3. For the effects of f and 5 on AAPD, see Figures 7 and 8. AAPD (1) is calculated from Equation (3. 9) with weighting factor, and AAPD (2) without weighting factor.

*Run temperature at 26.6°C.

bself-diffusion coefficients.

Page 122: Determination of molecular diffusivities in liquids

109

The results of using Equation (C.4a) in predicting the self­

diffusion coefficient of ethylene glycol with viscosities listed

in Table C.l at different temperatures are included in Table C.7.

It is found in this work that the simple empirical correlation

equation of Nagarajan et. al. can predic~ the self-diffusion

coefficient of ethylene glycol accurately to about ± 17%. Using

Gainer et. al. and Mitchell's technique with~= 6.0 and f = 0.99

can predict the value accurately to about ± 12%. Using Wilke­

Chang mutual diffusion e.'Tlpirical correlation equation accurately

to ± 15%. Therefore, ·the mutual diffusion relations can be used

to predict the self-diffusion diffusivity of ethylene glycol.

Page 123: Determination of molecular diffusivities in liquids

110

Table C.7

Comparison of Self-Diffusion Coefficient

of Ethylene GlycoJ_

6 2

Temperature oc D we

(If B=l. 0)

DAA x 10 , em /sec

D, Gainer et al. D, Mitchell D D exp exp ( ~ =6. 0) (f=O. 99 ,5=6 .. 0) (3. 9) (3. 9)

w

25 0.,837 0. 84-2 0.910 1.075 1.131 l.Oll-0

30 1.024- 1. 04-8 1.134- 1.328 1.330 1.278

4-0 1. 4-76 1.560 1.683 1. 94-9 1 .. 515 1.4-09

50 2.051 2.237 2.4-08 2.758 2.4-91 2.4-16

AAPD (1) 17.33 15.38 12.16 11.10

AAPD (2) 14-.81 13.79 10.89 14-.94-

* Notice: DAA are the values calculat~d by using Equation (C.4-a).

2) Results from Gainer et al. and Mitchell see Appendix Co2 and C.3.

3) AAPD (1) a.re calculated with Dexp value of (3.9) with weighting factor and AAPD (2) without weighting factor.

Page 124: Determination of molecular diffusivities in liquids

111

APPENDIX D

General Discussion

The following is the ge_neral discussion of (1) the effect of

calibrated effective mass ~rans:fer area and effective. mass trans.,-

fer length on rnolecular difftisivities~ (2) the treatment of the

eignvalue of equation - o(b = tan b in Equation (3. 7) or (3.8). n n ·

Page 125: Determination of molecular diffusivities in liquids

D.l The Effect of Calibrated Effective Mass Transfer Area

and Effective Mass Transfer Length o~ Diffusivities

112

In order to detennine the molecular diffusivities using the

porous frit technique for highly viscous solute-solvent s):sten1s,

the characteristics of the frit, such as effective mass transfer

area, effective mass transfer length and d..(= V f/V 5 ) must be

determined independently by using a system with a known diffusivity.

The calibrated values of AT and Leff are considered as the frit

constants and will be directly used in diffusivity determination

runs.

Using short time Equations (3.10) and (3.9) in determining

the molecular diffusivities, the effective mass transfer area is

the only characteristic of the frit used in runs. In least squares

analysis, using Equation (3al0) or (3-9), the product of AT and

DAB is always considered a curve-fitting parameter.. The value of

the diffusivi~Jr is found to be proportional .to the reciprocal of

the calibrated effective mass transfer area. In this work, the

frit constants were taken as the total average vaJ_ue of the indivi­

dual six frits. This was done because the standard deviation of

the average value for each cell from the value for all cells is

less than the deviation of the value for an individual cell from

the average for a particular cell. This difference in standard

deviation can be easily seen in Tables B. 4- and B. 5.

In this work, the effect of choosing AT for each individual

frit was also tested. It is found, however, that the dependency

of diffusivity on -temperature is erratic. For example, for run

Page 126: Determination of molecular diffusivities in liquids

113

66, DAB for ethylene glycol-diethylene glycol at 30°c is 0.825 x

10-6 cm2/sec, and in run 71 for the same system, but at 40°C, DAB

-6 2' is 0. 74·2 x 10 em /sec.

~Vhen using the long time equation, the calibra·ted Leff should

be used very carefully. Using Equation (3.7) in the least squares

analysis, one can easily find that the determined diffusivities

\~ill be proportional to the square of Leff when Leff is considered

a constant. However, there exists another parameter c1-, in Equation

(3.7), and is appropriately related to Leff in the form

(TI.la)

For 19 calibration runs (see Tables 1 and B.6), the values

from 2-variable and 3-variable search are 25.40 and 24.98, re-

spectively. These values of Leff (which are 0.531 and 0.556,

respectively for ·the 2-variable and 3-variable searches) can be

fitted to Equation (D.la). An example is given in Section 5.

However, out of 49 determination of diffusivity runs, only 22

ru.T1s have the determined d.. value and calibrated Leff which

satisfied Equation (D.la). The other 27 runs, say run 51, and

104 have ct values 45 and 36, respectively, and the molecular

diffusivities predicted are found to have larger values than

from Equation (3.9) with weighting factor. The calculated AAPD

for these two runs are found to be 120% and 105%, respectively.·

(see Diffusivity in Table B.13, run 51 and Table B.l8, run 104).

This shows that the calibrated Leff cannot be suitably used in

these 27 runs. This suggests that the calibrated Leff may not

always be considered a constant for a frit. This is possible

because (1) the soaking procedure of the fri t may not have been

Page 127: Determination of molecular diffusivities in liquids

114

uniformly constant and (2) probably the frit will soak up more

solvent if the viscosity of the solvent is low. The effect of run

temperature and time of soaking as well as the relative solute and

solvent viscosities may play an important role in determination of

the molecular diffusivities by using Equation (3.7) for long time

diffusion periods. Since this is the case, the actual physical

distance of the frit L (0.317 em) is also studied in this work.

The results of this prediction can be found in Table 4.

An attempt was made to determine the molecular diffusivity

using the long time Equation (3.7) by considering the effective

mass transfer length not a constant of a frit in determination of

the molecular diffusivity, i.e., Leff might be different for the

calibration ru..."'ls (low vlscos~ty) and diffusivity high viscosity

runs. This may be done by substituting o{ in Equation (3. 7) by

Equation (D.la). However, Vf may vary from run to run, depending

upon the number of samples taken during a run (although it should

be very close to 300 ml). In this work, the value of Vf is taken

from the average value of the calibrated Vf which may be calculated

from Equation (D.la) using calibrated Leff and o{ in calibration

runs.

The effective mass transfer B;rea of a fri t may be considered

as a constant (the same for poth calibration and diffusivity runs)

and a characteristic of the frit. The calibrated Vf from 2-

variable and 3-variable searches are included in Table D.l. The

calibrated Vf from 2-variable and 3-variable searches are 302.4

and 298.1 cm3 , respectively.

Page 128: Determination of molecular diffusivities in liquids

115

corresponding to five d.. values obtained in this work, with itera-

tion and with the recursion formula, are listed in the following

table:

* cf... bl b2 b2

16 1.603 4.725 4.744 21 1.587 4.719 q .• 728 25 1.587 4. 719 4.728 45 1.579 4. 716 4.720 60 1.579 4-. 716 4-.720

110 1.575 4. 714 4. 716

* where b2 are calclilated by using the recursion formula as follow-

ing

b - b . + (n - 1) Tf n 1 (n ==

where b1 is found via iteration.

1 2 3 --- 0<:)) ' ' '

Examining the eig:nfunction, one can easily see that - o( is

the slope of the curve of tan b n

' versus D • n

The absolute value

of the slope assumes a very large number because the difference

** between the values of Vf and Vs is very large. Therefore, the

effects of ( dbn) can be neglected. However, when o{ value do\

st-udies is very small, this is not always true. (see Figure 9).

Again, in order to find the bn (n= 1, 2, --- oO) , the iterative

procedure should be used. However, examining the value of b2 and

* b2 , one can see these two values differ by a negligible amount.

This is expecially true when theo< value is large. Therefore,

** v o< = f Vs

Page 129: Determination of molecular diffusivities in liquids

116

Table D.1

Calibrated Vf Values for Equation 1~

Run Cell No. of vf 3 a em

No. No. Data· . (3. 8) (3. 7)

1· 1 16 298.7 315.6 2 1 15 284.4* 293.2* 3 2 14 222.8 229.0 4- 2 17 302.4 312.7 5 3 15 291.2 295.2 6 3 18 269.7 277.8 7 4 17 276.2 280.9 8 I~ 16 325.5 329.7 9 5 13 274.4 279.5

10 5 15 3 44-. 7 356.3 12 1 15 277.4 286 .. 1 13 6 14- 326.7 329.8 14- 6 14- 305.7 315.7

105 1 11 309.9 302.1 106 2 15 334.4 329.9 107 6 11 244.8 274-.7 108 4 14- 34-4.7 341.4-109 5 12 326.3 329.4-110 3 12 24-0. 3* 248. 2*

Avg. l 292.7 299.3 2 318.'+ 290.5 3 280~5 286.5 4- 315.5 283.4-5 315.1 321.7 6 ·292.1 306.9

Total Avg. 302.4 298.1

* \ Results were not accepted.

avf is calculated using the e~lation: Vf -= 2AT L ffc/.. where· A is calibrated from short time model (3. 9) ; and Leff eand r:X are f~om long time Equation (3. 7) • ·

Page 130: Determination of molecular diffusivities in liquids

117

The curve-fitting parameters for the diffusivity runs using

the short and long time data are now Leff' DAB' and Cf0 • Equation

(3.7), after substituting~ from Equation (D.la), may be treated

by using the non-linear least squares technique described in

Section 4 and Appendix A.3. The results of these 2-variable

search, in which Cfo is a known quantity from Equation (3. 9) 5

and 3-variable search, in which Cfo is an unknown, are included

in Table 5, and compared with other models and correlation equa-

tions in Table 6. The diffusivity results show that Leff is not

a constant, i.e., not the same for calibration and diffusivity

runs, and the determined molecular diffusivities now agreed with

the results from Equation (3.9). This is in contrast to the case

when Leff calculated from the calibra.tion runs was used to calcu­

late diffusivities (see Appendix A.3); it will be recalled that

diffusivity calculated in this manner using Equation (3.7) did

not agree very well with the DAB calibrated using Equation (3.9).

The computer program and derivation of this least squares curve-

fitting program can be obtained by writing to Dr. R. M. Wellek,

University of Hissouri-Rolla, Rolla, Hissouri.

D. 2 Calculate the .Eignvalues of -D{ ~ = tan .Bu . The eignfunction -o(b =·tan b (n = 1, 2,---oo) used in n n

analysis of long diffusion time Equation (3.7) is treated in this

section.

Since b (n = 1, 2, ---oQ) is a function of o{ , the eign­n

values (bn) should be calculated by an iterative scheme. In this

study, the eignvalues of n = 1 and 2 are calculated by iterative

. + -10 method to within - 1.0 x 10 • The values of b1 and b2 ,

Page 131: Determination of molecular diffusivities in liquids

in order to find the value of b (n = 2, 3, --- otJ) recursion n

forrr~la developed in this work was used. Since b are weak n

function of o( ~ the value of b1 are calculated every time by

using iterative method when the value of ~ changes.

tan b n

Fig. 9.

b n

Graphic solution of - e:J. b = tan b n n

118

Page 132: Determination of molecular diffusivities in liquids

AT =

b = n

c =

DAA =

DAB =

ED,AB =

AEVAP =

Ep,B =

EP,X-H = f =

A F .Lt ,B =

AFD,AB =

~FD,XX =

AFD,XX-H =

.6.FD XX-D = '

h =

AHVAP -

L:.H = VAP,X-H

.AHVAP =

APPENDIX E

Nomenclature

2 effective mass transfer area of the frit., em

eignvalues of eignfunction: - o(.b = tan b · n n

119

solute concentration inside·the porous frit, g-rnole/ liter

solute concentration in the solvent bath, g-mole/liter

initial solute concentration in the solvent bath, g-mole/liter

initial solute concentration inside the frit, g-mole/ liter

2 self-diffusion coefficient, em /sec

mutual diffusion coefficient, ~m2/sec

activation energy for the diffusion process, cal/mole

internal energy of vaporization, cal/mole

energy to overcome. viscosity energy barrier, cal/mole

activation energy due to hydrogen bonding, cal/mole

ratio of the activation energy due to hole formation to the total activation energy in diffusion

activation free energy for viscous flow, cal/mole

activation free energy for bj:nary diffusion, cal/mole

activation free energy for self-diffusion, cal/mole

activation free energy due to hydrogen bonding, cal/ mole

activation free energy due to dispersion force bonds, cal/mole

-27 Planck's constant 6. 623 x 10 erg-sec

heat of vaporization, cal/ mole

heat of .vaporization due to hydrogen bonding, cal/mole

heat of vaporization of hornornorph compound, cal/mole

Page 133: Determination of molecular diffusivities in liquids

k=

R =

RA =

~ =

rAA -

rBB =

t =

T =

Tb =

V=

vf =

v = s

J.l. =

t, =

lfB ·­d.. =

0""=

Subscripts

120

Boltzmann's constant, 1.380 x l0-15 erg/deg

effective mass transfer length from the center to the surface of the frit, em

molecular weight of solvent

23 Avogadro's number, 6.023 x 10 molecules/mole

universal gas constant, 1. 987 cal/mole-deg

radius of particle A, em

radius of particle B, em

intermolecular spacing in pure component A, em

intermolecular spacing in pure component B, em

time, sec

absolute temperature, OK

normal boiling point, OK

molal volume of liquid, ml/mole-

volume of solven·t in the solvent bath, 3 em

volume of solvent in the frit, 3 ('JTI

viscosity of liquid, poise or centipoise

parameter describing the geometrical configuration of the diffusing molecular and its neighbors

the 11 association numbern for solvent B

volume ratio of the solvent in the solvent bath and the frit

standard deviation

A = solute

B = solvent

Page 134: Determination of molecular diffusivities in liquids

121

APPENDIX F

.!li£1iography

1. Bondi~ A., and D. J. Simkin, A. I. Ch.E. ·Journal,· 3, 4-73 (195 7).

2. Bird~ R .. B., W. E. Stewart, and E. N •. Lightfoot, ttTransport Phenomena", John Wiley and Sor:t' s, New York (1963), p. 29.

3. Gainer, J. L~, and A. B. Metzner~ A.I.Ch.E. - I. Chern. E. Symposium Series, No. 6~ 74 (1965).

4. Lightfoot, E. N., and E. L. Cussler, Selected Topics in Transport Phenomena, Chern. Eng. Prog. Symposium Series, No. 58, Vol. 61, p. 82. (1965).

5. Mitchell, R. D., Ph.D. Thesis, University of Missouri-Rolla, Roll~, Missouri (1968).

6. Perry. J. H., nHandbook of Chemical Engineeringn, 4th ed., McGraw-Hill Book Co., New York (1963), p. 3-196.

7. Ree, F. H., T. Ree, and H. Eyring, I. Eng. Chern., SO, 1036 (1952).

8. Reid, R. C., and T. K. Shert\'ood, nProperties of Gases and Liquids", McGraw-Hill Book Co., New York (1958), p. 549.

9. Ibid., p. 87.

10. Sherwood, T. K., and R. L. Pigford, "Absorption and Extraction11 , McGraw-Hill Book Co., New York (1952) , p. lJ.

11. Smith, J. M., and H. C. Van Ness, nchemical Engineering Thermodynamics";· 2nd ed., McGraw-Hill Book Co., Inc. (1959) ' p. 132. .

12. Tirnmermans, J., nphysico7 Chemical Constants of Pure Organic Compounds", Elsevier Publishing Co., New York {1950) , p. 491.

13·. Weast, R. c., S. M. Selby, and C. D. Hodgman, nHandbook of Chemistry and Physics'~ , 46th ed. , The Chemical Rubber Co. (1962).

14. Wilke, c. R., and P. Chang, A.I.Ch.E. Journal, 1, 25t~ (1955).

Page 135: Determination of molecular diffusivities in liquids

APPENDIX G

Computer Programs

The programs used for the computa·tion of the least squares

parameters are given in the appendix. They are prepared in

Fortran IV Language and were run on IBM 3 60 system.

122

There are b!Jo complete programs included in this appendix:

(1) Determination of molecular diffusivities using short

time Equations (3.10) and (3. 9). This program can

also be used for calibrating the frit by changing some

statements which are denoted by a, b, c, and d at the

end of the statements. ·

(2) . Calibration of the frit using long time Equation (3. 7).

This program can also be used for determination of the

molecular diffusivities by changing some statements

which are denoted by a, b, ---k at the end of the

statements.

The complete programs using Equations (3 .lO) and (3. 9) for calibra­

ting the frit, and using Equation (3. 7) for determining the

molecular diffusivities can be obtained by writing to

Dr. R. M. Wellek, University of Missouri-Rolla, Rolla, Missouri.

Page 136: Determination of molecular diffusivities in liquids

123

c 1"10H·HJD oF u='\sT S01HPFS TECH'li0UE f3.10l & (3.9) C Ci'ILCULATE THE \:f'L[CtJLI\R DIFFUSIVITY C JP=NU~BER OF EXPEPI~ENTAL DATA POINTS C JOT,JPF.JPU = START POINT,END POINT,POTNTS USED IN RUN C JPl,JP2,JPV = START POINT,fND DOINT,POINTS USED IN RUN C N=~HJ~.~REP. OF PA!~A~1ETERS

C JK=PU'~ ~~tr'"R£q

C AT,CO,VF=KNOWN ~PEA,INITIAL SQLUTE CONC., VOLUME OF BATH GllU RL E P R fC I 'S I 0~! fl ( 5, 5} , 0 { 5, 5) , X { 2 4) , T< 2 4 l , Y { 24) , CHU ( 24) DnUrLE PRECISIO~ CE(24l,OFF{ZJ,CFOC(2),SUMC2l,AAPD(2)

S,CF(24l,CJJf2J,STA{2J,WW(2) O'JU Bl E P R EC IS I .J!~ AT , C F G, ')C , C F GC, C 0, B C, 1\0, E 0, R 1 , ,!). 1, E 1, Y l

9,0EXP,OSQRT,OFRF,OABS,SU~l,SUM2,VF,OF,DET,ADJ

N=2 !..1= N+ 1 f)'J 90<1 JNIJ=l,SO !:iE'.IQ {1, 105) ,H,VF,CO ;~ ;=A f' ( 1 , 1 C 8 ) J K , ,J K V, J i< l! ., J K C , T E r~ RFADil,lQQ) JP,JPI,JPF,JPl,JP2 RCfd) (1,101} tT{!),I=l,JP) RE!>D ( 1, lO?l (Y{ Ild=ltJP) :H=1l.Cl9v0 ~.- Q I T F. ( 3 , t- 0 C ) J K ~ J K U , J K V , J K C \vP,.ITE{3,60ll ffl'-1 W~ ITf{3, 222) ~·l ') I T E ( 3 ' 7 8 9 ) A T T c 0 .J DIJ::-:J Pf-JP I +-1 ,JDV=J D2-J P 1 + 1 ':./'~!TE{3 1 l":l)C} JOI.JPF,JPIJ wqiTf (3,QC2J JPl,JP2,JPV n•J 2 2 r = 1, .J P

?.2 X! I )=DSQJ.'T(T( I))

a

b

C ** LEAST SQU4RE CUFVE FITTI~G W[THQUT ITERATION (EQ. 3-10) Vi-=300. C DO S 1 J'~X=Q

sq·.~xcY=O

su:-tx?Y=O S 1)\'l GY=O DJ 4't {:::JDI,JPF S lJI< V.:= S!JP·; X+ X { I } S 1 l~~XCY=S!Y1XCY+X{ 1} /Y{ I l SU~IOV=SUMltY+l.C0G/Y(I)

44 SII'·~X2Y=SU'1X2Y+Y.~ 1} >:--.:~z/Y{ I} 1~ C 1. ?l=SIJI\-11 C'Y A ( l ~ 1 ) = S W-1 X 0 Y :\(1,3}=JPU /1. ( 2 , 2): S U l.tX C Y

1\ ( .? , 1 '= stmx 2Y 1\. { 2 , 3 l = S U '~X C\ll ~AUSS(A,n,N.M1 CF0CCll=D{2,Ml 02=DSQRT(3.J416D01*VF/(4.00C*fO*AT)*0(1,~) DF-=02**2 o~F{ll=DF

D F= DFF ( l)

c

Page 137: Determination of molecular diffusivities in liquids

CFC=CFOO( U f)!J AA I=Jr>I,JPF

66 CF{I)=4.0DO*~T*CC*OSQRT{DFl*X(Il/CDSORTC3.l4l6DCl*VF) g+CFC

swq=o SlJ'-12=0 f)] RC I=JPI,JPF C l-IU { f ) = ( C F ( I ) - Y { I ) l I Y ( I ) SIJfH=SUM l+Crlll {I> *""'2

80 SU~2=SUV?+Dh8S(CHUCI)). A6DD(l)=lOC.COO/JPU*SUM2 SUM { 1 )=StJ"-11 DC. T= .~ {1, U * i\ ( ? , ? ) -1\ ( l t 2 H•~ { 2,1) A~JJ=Il.{2, 2) CJ,J ( lJ=AfJ/OET WW(ll=4.0QC*CC*AT/{DS~RT{3.1416DOJ*VF)

C ** LC:AST SQUI\RE ClJPVE FITTING N!TH ITERATION CEQ. 3-9) !\T=lC.?7DO

r· .....

V~=3JO.CDO-C.5D0*JPV

B .J=CFO-CO AJ=2.00C*AT*DSORT(DF)/VF

2 40 l) J l I= 1 , N O'J 1 J-=1,'1

l 1\(l,J)::::Q

88

2 124

OJ BR I-= .. JPl,JP2 E ::J=DEXP { (,\CO:< X (f))>:'*?)

El=EC*{l.OOG-OfQF{AO*X(I))) Ol=?.000*~C*X{l)**2*El-2.0D0/DSQRT(3.141600)*X(I)

YI=Yfil-CO t. { l, l ) =A ( l , 1 ) + { R r:,; ~:[) l H"* 2/ Y { I l A(l,2]=A{l,2J+BG*El*Dl/Y{I) A(l.3)=A{l 1 31+BC*Dl*(Yl-BO*Ell/Y{I) ~ f 2 , U = 1\ ( ?. , l l + '3 C * D l ,~, E l/ Y ( I ) l\ ( 2, 2)-= A { 2, 2 ) + f 1 ** 2/ Y { I ) A!2,3}=A{2,3}+F.l*{Yl-~O*Ell/Y(I) CALl G AU S S { A 1 0 , j\t, ~.q

IFf0l\liS(0(1,"1))-5 .. 00-0) 2,2d24 IF(0ARS(D{2,~))-S.00-9l 24,24,124 A:)= fl. C +0 ( l ~ M ) BJ=f\0+0{ 2,M} IfERATIGN START GD TO 240

124

24 DC=A0**2*VF**2/(4.0DO*AT**21 d

120

CFOC-=~O+CO

00 120 I=JPl,JP2 CECIJ=CO+AC*DFXP((AC*X(I)1**2l*{l.OOO-OERFCAO*X(l})) SIJMl=O SIJM2=0 i)fl 90 I=JPJ ,JP2 CH!H I )=(CE{ I )-Y{ I) )/Y( I)

S 1 HH=Sl.P~l+CHU{ I >**2 90 SUI,~2·=SU~"2+DA8S(CHU( I))

SU~-1{2l=SU""!l

AAP0{2)=lOO.COC/JPV*SUMl f) ET =A ( 1, 1 } * ~ ( 2, 2 ) -A ( 1, 2 )':< 1\ ( 2, ll

Page 138: Determination of molecular diffusivities in liquids

?\OJ=.'\ { 2'" 2} C .. LJ ( 2) =A DJ /DE T WA(2}=2e0DO*AT/VF C.-\ll DFUf\.1 {CJJ,JPI,JPF,JPl,JPZ,JDlJ JPV c>= CF y STA

0. 1 'l' OFF DC) 1 ' ~' ' ' ., l'" :\ ' ,J' . ' .....

~-Jq IT F { 3., 500) rn 100 I=l,JP iF ( I .l T. J P 1 IF(I .LT. JPI ~-Jf< I TE !"3., 50 3l GO TO 100

.OP. I .GT. JP2J GO TO 501

.nP. I .GT. JPF) GO TO 502 T ( I), X { I ) , Y ( I l , C F (I} , CE { I)

50 l HQ. In: ( 3,. 50 4) Tf Il , X 0 ) , Y ( I l srJ TO 100

502 WRITE {3,5C5} TCI},X(I),Y(Il,CE{I) 100 CONTINUE 9'?9 ~,.;r.nTF: (3,506) DFF(l),OC,CFOO(l),CFCC,.'\APD{l) 7 AAP0(2}

9,STA(U,STA{2) 101 FORMAT(6FlC.2) 102 FOPMAT(4015.7) 105 FQRMAT{2Fl0.5 1 015.7) 108 FlR~AT(5X,4I5 1 FlC.4) 109 FOR~AT{5X,5T5)

125

222 FORMAT{/6X,•CALCULATION THE MOLECULAR DIFFUSIVITIE$') 500 ;='ll<VAT(//lOX,•T(T}',8X,.'X{Il',6X, 1 Y(f),EXP. CONC. 1 ,5X.,

9 ' C F { I l , E 0 • 3- 1 C ' , 5 X , ' C r { I ) , E Q • 3 -Cl 1 , ! l 0 X , • SEC • , 8 X , ' S Q R T T 1

9,6X,'G-~OL/l(TEfl',9X,'G-MOl/LITER',8X,'G-MOL/LITER',/) 503 F0RMAT(6X,FIC.2,4X,F7.?,3X,Ol6.8,3X,D16.8,3X,Ol6.8) 504 F8R~AT(6X,Fl0.2,4X,F7.2,3X,Dl6.8) 505 FOPMAT(6X,Fl0.?,4X,~7.2,3X,Ol6.8,22X,D16.8) 5 8 6 F 0 ? u l\ T { I I S X , ' I,HJ!.. E C U l A R 0 [ f F U S I V ! T Y ' t 5 X , 1 { E Q • 3- 1 0 } ' , B X ,

9 1 D=•,nl6.8,IX,'(E0.3-9) ',Ol6.g,/6X,'CONC AT TIME '• 9 1 f::QU6LS ZERO {EQ .• 3-10J ',6X, 'CFO=' ,Dl6.B,lX, '{EQ.3-9) I'

9Dl6.8,/6X,' A.8S. AVE. PFRCENTAGE 0EV. (EQ.3-10J' 9, l x, I A..A.P.D.=' ,DlA.R, IX,! (f0.3-9) ',Dl6.8,/6X, 9 1 STANDARD OEVIATIO~ IN OAR {EQ.3-10) STAR=',Dl6.8, arx,•<E0.3-9) •,016.81

789 FJRMAT(/6X, •MASS TRANSFER AREA FROM STANOARIZATION AT= 1

9 1 F1C.5,//6X, 1 PliTil\L SOLUTE CONCEr-.JTRATION IN FRIT',3X, 9'C0= ',016.8)

600 ~DRMAT{1Hl,//////////6X 1 1 RUN =',f3,4X,'S0LUTE = •,13, 94X,•SOLVENT = •,T3,4X,'FRIT CODE= •,13)

601 f:.JRI'HIT!16X, 'TH'~PfPATUPE =' ,f-10.4) 900 FOR~AT(/6X, 'EQ. 3-10 DATA POINT FRO~',I3,' T0',13,2X,

9'TOT4l POINTS= ',13) 902 FOPMAT{/6X,'EQ. 3-9 DATA POINT FROM',I3•' TO•,I3,2X,

9'T0Thl POINTS= ',!3) STOP END SURROUTINE GAUSS(A,D,N,M) DOUP:LE PRECISION ld5~5),0{5,5l,C!1,5),fEST

9,DII,OJ,OJII,DABS DO 1 l I= 1, f'.J on 11 J= 1, M

11 O{I,jl=A(I,J) 00 60 I=l,N

Page 139: Determination of molecular diffusivities in liquids

K l= I T F ( I -1\l ) 5 2 , 3 g , 3 9

52 N2=0 NK=N-K 1 + l TEST=O DO 12 Il=Kl,N IF(D(!l~l))l3,14,13

11 TEST=TEST-OABSCD( Il, Il} !F(TEST)l5,l2,12

15 TEST=DABS{D(Il,!)) l 0 R=Il G'J TO 12

14 i·J2=N2+1 IFIN2-NKll?,l6,16

16 1-F~ rTF:( 3, 200 J 200 ~OR~ATI//15X,'SINGULAR MATRIX')

GO TO 9 9 STOP

12 CONTINUE C)] 51 K2=Kl,M C(J.,K2)=0(IPR,K2) :J!IDR,K2l=O{l,K2)

51 0!I,K2)=C(l,K2) 39 or I=<'{ r, I l

i) J 4 C; K 3 = K l , ~ 4J 0{I,~3)=0ti,K3l/OII

DO 6C1 Jl=l,I\.J OJll=O(Jl,U f!={Jl-I )30,60,30

30 08 62 K4=Kl,~ 62 D(Jl,K4J=O(Jl,K4)-0J1I*D{I,K4l 60 CONTINUE

RETURN END SURPOUTINE DFUN CCJJ,JPI,JPF,JDI,JP2,JPU,JPV,CE,CF,

QY,STA,WW,OFF,DC) DOUBLE PRECISION CJJ(2J,CE{20),CF!?OJ,YC20},STA{2),

9V AC ( 2) tV AP ( ? ) 1 SO { 2 1, OFF ( 1) , ~-JW ( 2) DOUBLE PRECISION DSORT,DAR$ 7 0C S Q { 1 } -== 0. 0 DO SIJCZl-=O.COO DO 2124 I=JPI,JPF

2124 SQ(lJ=SQ(l)+(CF(I)-Yfl))**2 DO 3124 I=JPl,JPZ

312'+ s.J(2)=SQ!2JHCECI)-Y(JJ)**2 VAC(l]=SQ(lJ/(JPU-2) VAC(2}=$0{2)/(JPV-2l VAP(l)=VAC{ll*CJJ(l) VAPC2l=VAC{2)*CJJ(2J ST/d J.}=OSQRTCDA8S{Vi\P( 1) J)

STA(2J=DSQRT(DARS{VAP(2))) S T td 1 ) = D SQR T ( D FF ( 1 ) ) /h'W { 1) *S T A ( 1) STA(2J=OSQRTCDCJ/WWC2l*STA(2) RETURN P~D

126

Page 140: Determination of molecular diffusivities in liquids

~Totice: For calibrating the frit, the following statements

should be used.

a. READ (1,105) DF, VF, CO

b. WRITE (3,789) DF, CO

c. AT = DSQRT(3.1416DO)*VF/(~.O*CO*DSQRT(DF))

*D(l,3)

d. AT= AO*VF/(2.0DO*DSQRT(DF)).

127

Page 141: Determination of molecular diffusivities in liquids

128

C LEAST SOUARF PPOPLEM nF LONG DIFFUSION TIMF EQUATION C RfNl IS WEAK FUNCTION DF ALPHA : -A*B(NJ=TANfB(NJ) C JD=NU~BER OF EXPERIMENTAL DATA POINTS C JPI,JPf,JPU = STA?T PriNT,ENO POINT,POINTS USED IN RUN C N=~U~BER OF PARAMETERS

OJUP.tE PRECJSIOI\1 P.f42l,X(20l,T{20J,Y{20) 1 S(4,4l,SS(4,4) a,CF{?OJ,CEC20),CF1{20J,CE1(20J,AL{2J,CJJ(2),STA{2) 9,!)(4,4)

D1U9LE PRFCISIO~ A,~E,CO,CFO,DF,Fl,Gl,E0 1 AK,BK,PC, 2 S !J MAK ::>, S U~A KO t SlH'-~ll. Kct, P 1, Q 1, R 1, AAPO, DE XP, DEL 1\, DElE, f.C 1, OA2,A3,AE2,AE3,AAPD2,AAP03,SUMR2,SUMR3,CF02,CF03,B2,83, 981, SUMR 1 , AA P D l t A 1. A E 1 t DE T, -~OJ, AT, VF 2, VF3 9 1 DSORT,OA9S,EPS,CC2,SUMR

no ng9 IJ=l,zo qeADfl,lC5} DF,CO,CFO P~AQ (1,103) AE,A q~~D{l,lCS) JK,JKV,JKU,JKC,TEM READ {1,109) JP,JPI,JPF o:;AO (1,101) (T(I).,I=l,JP) READ (1,102) (Y{Il,T=l,JP)

C ** LEAST SOUA~ES TECHNIQUE : TWO VARIBLES 1\J-= 2 '-1=N+l JPU=JPF-JPI+l E'J=DF/liE**2 Gl=CO-CFO "'1K=:40 E?Sl=O.O 1 D~ 4C I=l,JP

40 X{ I l=OSQRT{T{ I)) . C4ll. JE~N{A,AE,JP,JPI,JPF,JPU,JK,JKV,JKU,JKC,TEM,T,B,Y

0,X,F0 1 DF.,CO,CFQ.,~D,Fl,Gl,AAPO,CF,SUMR) :~l-=1\

AEl=AE Bl=B( 1) DD 3 KL=.J?[,JPF

3 CFHV.:L)=CF{Kl) CCl=A~PO t\.1\PDl=.AAPU Sut1R 1-=SUMR DO 9997 TJK=l,20 IYJ 1 I=l,N DO 1 J=l,M

1 SS{f,Jl=O !)!] 80 !=J 0 [ ,JPF SUf41~KP-==O.

5!.1:•1/l.KR=O. S'Jiv'!}\1<0=0. O!J AO K=l,.NR ~K=A/(l.OOO+A+A**2*B{K)**2) PC=EO*BfKl**Z*TCI) fC{DI\BS{PC} ~GT. G.50D2l GO TO 1000 8K= DEXP (-PC) SUMAKP=SU~AKP+2.0DO*AK*BK . * * SUMAKO=SUMAKQ+2.000*{AK*qKJA-AK~*l/A BK

a

Page 142: Determination of molecular diffusivities in liquids

9{l.C00+2.00C*A*A(K)**2)} 60 SUM4KR=SU~~KR+2.0nO*(AK*T(I1*B{K)**2*BK)

l 000 Cf1NT INUE Pl=Fl-SUMAKP Ql=Fl**2+StJMAKQ Rl=SU~AKR

Yl=Y{!)-CFO St 1,1 >=Ol**Z*Gl 5{1,2)=-Rl*Ol*Gl $(1,3>=01*(Pl*Gl-Yl) S ( 2, U=R l*Ql*Gl Sf2,2)=-Rl**2*Gl S{2,3}=Rl*(Gl*Pl-Yll ssn, 1 )=sse 1,1 l+S( 1, u SS(l,2l=SS( 1,2)+$( 1,2) SSCl,3)=SS( 1,3l+S( 1,3) S~{2,1l=SS{2,ll+${2,1)

SSf2,2)=SS{2,2l+S{2,2) 80 SS(?,3)=S${2,~)+S(2,3)

CAll GAUSS[SS,O,N) CJJ<U=OC2,2) DELA=D( 1, 3) DFLE=D(2,3) A= A+DEL A EO=fO+DELE IFIEC' .t T. C.CDO) GO TO 97

1.29

AE=DSORT{OF/[0) b C~ll JEAN(A,AE,JP,JPI,JPF,JPU,JK,JKV,JKU,JKC,TEM,T,B,Y

a,X,EC,DF,CO,CFO,MR,Fl,Gl,AAPD,CF,SUMRl CC2=AAPD

C ITERATION STARTS IF{l),~A${ CCl-CC2l-EPSU S8,9R,9998

98 IF(C(l .LT. CC2l GO TO 97 CJJCU=DC2,2) A2=A AF2=AE c CFC2=CFO Ai'IPD2=AAPO SU~1R 2=SUMR B2=B(l) GO TO 94

97 A2=Al AEZ=.~El

CFOZ=CFO J\APD2=AAPOl S~H1R2=SUMR1

B2=81 DO 4 Jl=JPI,JPF

4 cc {Jl l=CFlf Jl l -\=A 1 AE=AEl GO T0.94

9998 CCl=CC2 Al=A AE 1= AE

d

e

f

Page 143: Determination of molecular diffusivities in liquids

13l=P(l) ~.~POl=CCl

D"J 5 KJ=JPI,JPF 5 CFl(KJ)=CFfKJl

9907 CJNTINUE

C ** LEAST SQUARES TECHNIQUE : THREE VA~IBLE$ gt+ N= 1

"l·=t~+ 1 F'J=DF/ A.E**2 Gl=CO-CFO

130

C!ILL JOHN{~7AE,J:~J~I,JPF,JPU,JK,JKV,.JKU,JKC,TEM,T,B,Y 9,X,EO,OF,C~,CFO,~R,Fl,Gl~AAPO,CF,SU~RJ ~l=A

AEl=AE B l=P { 1) o·J 7 KL=JPI,JPF

7 CEUKLl=CE{Kl) CCl=AAPD A•"'PDl=AAPO SIJMR l=SUMR DJ 09qg IJK=l,ZO D'J 2 I=l,N DO 2 .J=l,11.1

2 SSfi,J)=O. DD q(; l=JPI,JPF SUMAKP=O. SUMI\KQ=O. SUM,~KR=O.

DO 70 f{=l,MR ~K=A/(l.OOC+A+A**2*B{K}**2l PC=EC*B(K)**2*T(IJ IF{f!,'\RS(PC) .GT. C .. 5CD2) GO TO 1001 ~I(=DEXP{-PCl

SUMAKO= S U"~A K Q + 2. CD C>H l\ K *SKI A -Al\ *>:'2 I A*BK* 9{l.GDC+2.0DC*A*P(KJ**I))

70 SUMAKR=SU~AKR+2.GDO*IAK*{T(Il*[B{Kl**2ll*BKl 1001 C'JtHINUE

Pl=Fl-SUMAKP Q l =F 1** 2 +SIJM.A KQ R l= SU"~AKR Yl=CO-Y(l) S { 1, l) =G 1 1~Q 1 ;'< ( 1 • OD 0-P 1 l S ( 1., 2l =- ( G l ,~ R 1 * { 1. 00 G- P 1) )

s ( 1 ' 3) = { 1 • 0 0 0- p 1 ) * * 2 ${1 1 4)=-(Gl-Gl*Pl-Yl)*{l.COC~Pl) S(2,l)=!Gl*Oll**2 S(2,2J=-Gl*Rl*Gl*Ql S{ 2, 3)=( l.COO-Pl l*Gl*Ql $(2,4)=-C~l-Gl*Pl-YlJ*Gl*Ql $(3, U=Gl~*2*0l*Rl S{3 1 2)=-(Gl*~l}**2 S(3,3l=ll.ODC-Pll*Gl*Rl $(3,4)=-(Gl-~l*PI-Yll*Gl*Rl SS{l,ll=S<;{l t ll+S{ 1,1)

g

Page 144: Determination of molecular diffusivities in liquids

SS(l,2)=$S{ l,;::)+Sf 1,2) .S){l, 3)=$${ 1.,3)+5{ 1,3) SS(1,4)=SS(l,4)+S{ 1.,/t} <;S{?, 1 l=SS{2., l}+S{ 2,1) SS (2, 2l=SS{ 2, 2}+$( 2, 2) S S { 2, 3) = S S { ?., 3) +S{ ? , 3 l SS(2,4)=SSC2 1 4)+S(2,4) SSC?,l}=SS(3,1HS{3,ll S'S{3,?.l=SS(3,2)+SC 3,2) SS{3,3}=SS{3,3)+S{3,3}.

90 SS{3,4 l=SS{ 3,4)+S( 3,4) C!LL GAUSS<SS,O,N) C,iJ{2}=0{2,2) '\=A+O( 1,4) I:J=E0+0(2,4l Gl=Gl+D{3,4) IF(EO .LT. O.COO) GO TO 91 1\~=DSORT(DF/EC)

C l-O=CO-G 1

131

h

C~LL JOHN(A,AE,JP,JPI,JPF,JPU,JK,JKV,JKU,JKC,TEM,T,B,Y 0,X,E0,DF,CO,CFO,MP,Fl,Gl,AAPD,CF,SUMR)

CC?=AADO C !TfR~TION STARTS

(C(Q~BSCCC1-CC2)-EPS1J 99,90 7 9996 99 IFfCCl .LT. CC2) GO TO 91

A 3"= 1\ A':3=AE cr-03=CFO AI\PD3==AAPO StJI.AR 3-=SlJI-1R R ~=? { 1}

GCl TD 96 01 1\3=.1\1

.-\ E3=AF.l CF03=CFO >\i\PD3=AAPD1 SlH.IlR 3=SUMR 1 133=Rl I)CJ 8 JL=JPI,JPF

8 CECJL)=CEUJL) GO TO 96

9996 CCl=CC2 Al=A AF.l=AE Bl=Rfl) AI.\POl=CCl OQ o JL=JPI,JPF

q CF.lfJL)=CE(JLl 9999 CONTINUE

96 C'lNTINliE C~LL DFU~ (CJJ,JPI,JPF,JPU,CE,CF~Y,STA) i\T=l1.019DO VF2=2.GDO*AT*A2*AE2 VF3=2.0DO*AT*A3*AE3 W~ITE {3,600) JK,JKU,JKV,JKC

i

j

k

Page 145: Determination of molecular diffusivities in liquids

WQITE(3,6Jl) TEM WUTF( 3, ?.22) WqiTE {3,900) JPI,JPF,JDU W~ITEf3,90Cl) DF,CO tn ITEt 3, 500) ~):l 100 I=hJP I F ( J .LT. J PI • 0 R. • I • ST. J P F J G 0 TO 7 2 H'UTf{3,50U T( n,X( IJ ,Y{ f l,CF{I) ,CE{I) GJ TO 100

7 2 :·n I T E { 3 , 50 3 ) T[ l) , X ( I r, Y 0 ) 100 CONTI ~'~tUE 999 W~ITE(3,~02) A2,43,AE2 1 AE3,CF02,CFO~,~AP02,AAP03

o,92,~3,VF2,VF3

STOP 1 0 1 F J R VI. 4 T ( 6 F 1 0. 2 ) 102 FOFMAT{4015.7) 103 FJRMAT(?Dl5.7} lCS FJR~~T(3015.7) 108 FJRMAT(5X,4IS,FlC.4) 109 FJP~AT{5X 1 3[5)

132

222 FQPMAT{/AX, 1 CALIBRATION, LONG DIFFUSION TIME EQUATION' q;~X,t([Q.3-8) FOP ?-VARIABLE SEARCH,• 91X,'IEQ.3-7) FOF ~-VARIABlE SEARCH')

50 0 F 0 R i'-1 AT { I 11 C X , 1 T ( T ) ' , P X, ' X ( I ) • , 6 X , ' Y f I ) , EX P. C 0 NC • ' , 5 X 1

9'CF(Il,E0.3-8 1 ~5X,'CFCIJ~E0.3-7',/10X,'SEC',8X,'SQRT T' 9,~X,'G-MOL/lTTEP',RX,•G-MOLILITER',AX,'G-MOl/LfTER',/)

501 F~RMAT(6X,~l0.2,4X,F7.2,3X~Dl6.R,3X,Dl6.9,3X,Ol6.8J 503 F0R~ATf6Xtfl0.2,4X,F7.2,3X,Ol6.8J 502 F•JlW1~T(II6X, 't..LPH!I = Vf/VS CEQ. 3-8} A='

9,nl6.8,2X,'{E0.3-7) ',Dl6.A, 9/SX,'EFFE. TPANSFEP LE~GTH CEQ. 3-8) L=',016.8, czx,•(EQ.3-7J ' 1 016.8, 9/AX,'INITIJ\l COT'·'C. IN BATH CEQ. 3·-8) CF0=',016.8, G2X,'(EQ.3-7l ' 1 Dl6.8, G/6X, 1 ABS. tVF. PFR. DEV. {EQ. 3-SJ A.A.P.0.=',016.8 1

92X,' {EQ. 3-7} 1 1 016.8, 9IAX,eFIRST fiGENVALUE 3(~) {EQ. 3-8) B(l)=•,Dl6.8, 9 2 x, • u: o • 3-n ' , ~n A. e, 9/6X, 1 VOLU~E RATTO OF FLUID CEQ. 3-Bl VF=',Dl6.9, 9 2 X ' I { E () • 3-7 ) • ~ Dl 6 • B )

6 0 0 F J R 'I. AT { 1 H 1 , II Ill I I I I I f., X , 1 R U\l ·= ' , I 3 , 4 X , ' S 0 L 1J T E = 1 , I 3, 94X,'SOLVENT = 1 ,I~,4X, 1 FRIT C01E = •,13)

601 F0PMAT{/6X,'TEMPERATURE =',Fl0.4) 9 0 0 ~ 0 F M AT f I 6 X, 1 0 AT ~ P 0 I NT f R 0 ~4 1 , I 3 , ' T 0 ' , r 3 , 2 X ,

? 1 TOT~L POINTS= ',13) 9001 FORMAT(/6X,'DAB=',Dl6.~,4X,'CC=',Dl6.3)

EI\ID SUBROUTINE GAUSSISS,O,NJ OOURlf PRECISIO~ SS(5,5J,D(5,5),C{1,51,TEST,

9n[J,OJ,DJII,OABS M=N+l D!J 11 I= 1, N o:J 11 ,J= 1, M

11 O(f,Jl=SS{f,J) on nO I=l,N

Page 146: Determination of molecular diffusivities in liquids

Kl=I IF( I-N)52,39,39

52 N2=0 N!<=N-K 1 + l TEST=O D!l 12 Il=Kl,N IF{OCII,Illl3,14,13

13 T~ST=TEST-DAq${0(11 7 1)) JC(TESTJ15,12,12

15 T~ST=DAOS( Of I 1, Il} JOR=I1 GfJ TO 12

14 N2=N2+1 JC(N2-NK}l2,16,16

16 W~ITEf3,200} 200 FQRMAT{//15X,'SINGULAR MATRIX')

G,J TO 9 9 STOP

12 CONTINUE 01 51 K2=Kl,M Ctl,K2l=DCI?R,K2) Of IPR,K21-=0( I,K2l

51 1J{I,K2J-=C(l,K2) 10 DI I=Q( I, I)

0'1 40 K3=K 1, M 40 D(I,K3)=0(I,K3l/Dli

O'J 6C Jl=l,N DJli=D(Jl,I) IF{Jl-!}30 7 60,30

30 D8 62 K4=Kl,M 62 ry(Jl,K4)=D(Jl,K4)-0J1I*O{I,K4) AO CDNTJ\lUE

RETURN ENO SUBROUTINE JEAN{A,1\E 9 JP,JPI,JPF 7 JPU,JK,JKV,JKU.,JKC,

9 T EM , T , i3 , Y , X , E C, D t-, C C , C F 0 , MR. t F 1 , G 1 , A A P f) , C F , S U MR ) DOUBLE PRECISIQt.! T{20),B(50J,Y(20J,CFl20i,CHU(20) 9

9X(20l,F{5),BN{5l DOUBLE PRECISIO;..! A,AE,DF 1 CO,CFG,.AAPD,:\K,PC,EO.,Fl-,Gl• 2SUMP,SU~l,DAeS,OEXP,Bl,OTAN,BK,SUM

C ** FIND THE ROOTS OF -A*A(N}=TAN!B(N)) E P S = 1. 0 D- 10

43 B~(ll=1.571DO Bf\J{2l=1.7000

17 B~(J)=(BN(l)+BN{2)J/2.000 O'J 2 3 K 1 = l , 3

23 F(Kl)=A*BN(Kll+DTAN(BNCKl)) IFfF(3) .LT. EPS) GO TO 6 IF(F{3)*Fil)) 986 1 6,985

9 8 6 B N { 2 ) = BN ( 3 J GO TO 17

9 8 5 13 ~H 1l = BN f 3 l GO TO 17

6 8l=PN(3) 00 22 NR=l, fl-1R

l33

Page 147: Determination of molecular diffusivities in liquids

c

22 3{NR)=Rl+CNP-1)*3.14DO Fl=l .nOC/(l.ODO+Al D1 160 I=JPI,JPF SU~'ll =0. DO 1'5q K=l,~AR AK=A/(l.ODO+A+A**2*P{K)**2} PC=EO*B(K)**2*T{J) I!=(OA8S{PC) .C:.T. 0 .• 5002) GO TO 160 S•<=DEXP {-PC)

159 Slll-il=SUM 1 +2. ODO*AK*BK 160 C~Cil=CFl-SUMl)*Gl+CFO

$1.)\~R=O.

D1 120 I=JPI,JPF CHIJ{ fl={C:Ffi )-Y( Il )/Y( I} SU~R=SUMP+CHUCil**2

120 SIJM=StW+DABS ( CHU( I)) A~PO=lOO.ODO/JPU*SUM RE TUR~~

** 43

17

23

986

985

6

22

PID SU'3POUTINE J8Hf\l(A,AE,JP,JPI,JPF,JPU,JK,JKV,JI<U,JKC,

9T,B,Y,X,EO,OF,CO,CFO,MR,Fl~Gl,AAPO,CE,SUMR)

DOUPLF P~ECISION T(20),B{5C},Yf20l,CE{20) 7CHU(20J, 9X(2Q),Ff5),F~f5)

DGURLf PRECISION A,ll.E,DF.,CO,CFO,AAPO,AK.,PC,EO,Fl,Gl, 2SU~R,SUMl,DABS,OEXP,Al,DTAN,BK,SUM

FIND THE ROOTS OF -A*B(N)=TAN{8(N)) EPS=l.OD-10 ~\j { 1 )= 1. 57100 B\1{ 2 )= 1 .. 7000 3~{3}={8N(l)+PN{2))/2.000

f)'} 2~ I{ l-= 1' 3 F(Kl)=A*AN(K1J+OTAN(BN(Kl)) IF ( F { 3) • LT. EP S) GO TO 6 JF(F{3}*Ffl)) 986,6,985 B!\H?l=B".J{3} GO TO 17 8 \l ( 1) = BN ( 3 ) G!J TO 17 Bl=BN ( 3) DIJ 22 NR=l,MR 3(NR)=Bl+{NR-1)*3.1400 Fl=l.ODO/(l.ODO+Al DO 160 I=JPI,JPF SUMl=O.OOO 0') 159 K=l,MR AK=A/{l.ODO+A+A**2*R(1<)**2) PC=EC*B(K)**2*TCI} IF(OAGSCPC) .GT. 0.5002) GO TO 160 BK=DEXP(-PCJ

159 Sl1Ml=SUM1+2.0DO*AK*RI< 160 CE(I)=(CFO-CO}*(l.ODO-(Fl-SUMl))+CO

SUM=O.C Stfi'4R=O .0 08 120 I=JPT,JPF

134

Page 148: Determination of molecular diffusivities in liquids

C HU ( I } -= ( C E { I } - Y ( I ) l/Y { I ) S1J MP = SW·H: +CI-11..1 (I l ** 2

120 SUM=~U~+DARS(CHU{I)l A~PD=lOO.ODO/JPU*SUM

RETURN PW

Notice: For. determination of the molecular diffusivi ties, the

following s·tatements should be used.

a. DFl = DF

b. DF = EO*AE**2

c. DF2 = DF

d. DF2 = DFl

e. DF = DFl

f. DFl = DF

g. DFl = DF

h. DF = EO*AE**2

i. DF3 = DF

j. DF3 = DFl

k. DFl = DF

135

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136

VITA

The author, Pai-Chuan Wu) was born on August 15, 1942, in

Changhua, Taiwan, Republic of China. He received his secondary

education in Taiwan Provincial Changhua High School. He entered

Tunghai University in Taichurig, Taiwan in September 1961 and

graduated in June 1965 with a Bachelor of Scj_ence Degree in

Chemical Engineering.

After graduation, he served in the Republic of China Army as

a 2nd Lieutenant from July 1965 to July 1956. Then he served for

one year, from August 1966 to July 1967, as a teacher of Physics

and Chemistry in Taiwan Provincial Changhua High School.

He has been enrolled in the Graduate School of the University

of Missouri-Rolla since September 1967.