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Isfahan University of Technology Department of Chemistry. Continuous Synthesis and Separation of Glycerol Acetates Using Supercritical Carbon Dioxide as a Benign Solvent. By: Marzieh Rezayat. Supervisor: Prof. H. S. Ghaziaskar Advisor: Prof. M. Yalpani. Aug 10, 2010. Outline. - PowerPoint PPT Presentation
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1
Isfahan University of TechnologyDepartment of Chemistry
Continuous Synthesis and Separation of Glycerol Acetates Using Supercritical Carbon Dioxide as a
Benign Solvent
By: Marzieh Rezayat
Supervisor: Prof. H. S. Ghaziaskar Advisor: Prof. M. Yalpani
Aug 10, 2010
2
Introduction• Supercritical Fluids • SCCO2 Properties
• Chemical Reaction in SC-CO2
• Extraction & Separation by SC-CO2
• Glycerol acetates Experimental
• Synthesis of acetins• Separation using SCCO2
Conclusion
Outline
3
Supercritical Fluid18
2218
9819
1319
90s
4
Historical Development of Patents Issued in Different Fields of Supercritical Fluid Technology
5
•
SOLID
GAS
LIQUID
SUPERCRITICALFLUID
Triplepoint
Criticalpoint•
Pre
ssur
e (b
ar)
Temperature (ºC)
74
31.1ºC-56.3ºC
5.1
-78 ºC
1
Phase diagram for pure CO2
6
Chemical Reaction in SC-CO2
Low Density
and Viscosit
y
Heat transfer
7
8
Extraction & Separation by SC-CO2
Effect of extraction parameters:
• Pressure and Temperature
• Difference in density between the liquid and SC-CO2
• Time
• Feed/Solvent
9
Countercurrent Supercritical Fluid Extraction
10
Supercritical Fluid Fractionation
11
Synthesis of Glycerol acetate
R2OCOHC
CH2OCOR1
CH2OCOR3
+ 3CH3OH HOHC
CH2OH
CH2OH
+
CH3OCOR1
CH3OCOR2
CH3OCOR3
Triglyceride Methanol Glycerol Methyl esters(biodiesel)
12
Conventional Methods
Glycerol +Acetic acid
Acetic anhydride Organic Solvent
Acid Catalyst
Monoacetin(MA)
Diacetin(DA)
Triacetin(TA)
Problems
ColoredOdorous
Impure
13
Synthesis of Glycerol acetate
HO OH
OH
+
HO OCOCH3
OH
CH3COOH
HO OH
OCOCH3
HO OCOCH3
OCOCH3
H3COCO OCOCH3
OHH3COCO OCOCH3
OCOCH3
+ ++ H2O
Glycerol Acetic acid
Monoacetylglycerol(MA)
Diacetylglycerol(DA)
Triacetylglycerol(TA)
14
Continuous Flow Reactor
15
CO2 (99.95%) Glycerol (>98%) Acetic acid (99-100%) Absolute Ethanol (>99.0%) 1-hexanol (Riedel-deHaën) Triacetin (99.0%) Diacetin (50%) Monoaectin (synthesized) Amberlyst15®
Materials
16
Synthesis of Monoacetin
HO OH
OH
PTSA
Acetone - CHCl3O
OOHH3C
H3C
1 2(AcO)2O
O
O O CH3
O
H3C
H3C
3
AcOH 70%
HO
HO O CH3
O
Monoacetin
17
Analytical methodThe yield, conversion, and selectivity for each sample are calculated as follows:
Yield =Total moles of detected esters
× 100Moles of glycerol in feed solution
Conversion = Total moles of detected esters × 100Moles of detected esters and glycerol in exit flow
Selectivity =Moles of each ester
× 100Total moles of detected esters in exit flow
18
Amberlyst15®
19
Pressure Temperature Molar ratio (Acetic acid/Glycerol) Flow rate Reactor geometry Time
Continuous Synthesis of Glycerol Acetates in SC-CO2 Using
Amberlyst15®
OH
HO
HOk1
CH3COOH
HO
OH
OCOCH3k2
CH3COOH
H3COCO
OH
OCOCH3k3
CH3COOH
H3COCO
H3COCO
H3COCO
Glycerol
MonoacetinDiacetin Triacetin
HO
OCOCH3
OHH3COCO
OCOCH3
OH
20
Pressure:
0 50 100 150 2000
20
40
60
80
100
300 bar
250 bar
200 bar
Time / min
Tri
acet
in S
elec
tivity
/%
0 50 100 150 2000
20
40
60
80
100
65 bar80 bar150 bar
Time / min
Dia
cetin
Sel
ectiv
ity/%
0 50 100 150 2000
20
40
60
80
100
65 bar80 bar150 bar200 bar250 bar300 bar
Time/min
Mon
oace
tin S
elec
tivity
/%
21
Pressure:
65 80 150 200 250 3000
20
40
60
80
100
Conversion / %
Yield / %
MA Selectivity
DA Selectivity
TA Selectivity
Pressure /bar
Sele
ctiv
ity, C
onve
rsio
n or
Yie
ld /
%
22
Temperature:
100 120 140 1500
20
40
60
80
100Conversion / %Yield / %MADATA
Temperature /°C
Sele
ctiv
ity, C
onve
rsio
n or
Yie
ld /
%
23
Molar ratio (acetic acid/glycerol):
1.5 4.5 6 12 18 240
20
40
60
80
100Conversion / %
Yield / %
TA
DA
MA
Substrates molar ratio (acid/glycerol)
Sele
ctiv
ity, Y
ield
or
Con
vers
tion
/ %
24
Condition Conversion (%) Yield (%) TA (%) DA (%) MA (%)1a 35 29 0 0 1002b 100 41 100 0 0
Reactor length :
A without catalystb with catalyst
Reactor Length (cm) Conversion (%) Yield (%) TA (%) DA (%) MA (%)25 100 41 100 0 0100 100 48 82 19 0
Catalyst :
25
Times catalyst recycled Conversion (%) Yield (%) TA (%) DA (%) MA (%)3a 100 82 27 42 313b 100 49 92 8 0
Catalyst reusability:
a acid/glycerol ratio was 6.0. b acid/glycerol ratio was 24.
0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.00
20
40
60
80
100 Yield / % TA DA
Time/h
Sele
ctiv
ity o
r Y
ield
/ %
26
0.0 2.0 4.0 6.0 8.0 10.00
20
40
60
80
100
Yield% Polynomial (Yield%) TA% DA%
Time/h
Sele
ctiv
ity o
r Y
ield
/ %
0.0 2.0 4.0 6.0 8.0 10.0 12.00
20
40
60
80
100
Yield% Polynomial (Yield%) TA% DA%
Time/h
Sele
ctiv
ity o
r Y
ield
/ %
Acetic acid/Glycerol= 30
Acetic acid/Glycerol= 40
27
The result of feeding 1st reaction effluent through the fresh catalytic bed This mixture has been synthesized at the ratio of 24, 200 bar, 110
ºC with the final composition of 64.3% TA, 35.7% DA
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.00
20
40
60
80
100
TA% DA%
Time/h
Sele
ctiv
ity /
%
28
% Selectivity and %Yield vs. CO2 flow rate
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.00
20
40
60
80
100
Yield% Polynomial (Yield%) TA% DA%
Time / h
Sele
ctiv
ity o
r Y
ield
/ %
Flow rate= 3.0 mL.min-1
29
Silica Sulfuric acid
30
Catalyst bed: 4 mm (i. d.), 25 cm (length) T = 110 °C Flow rateSub.=0.2 mL.min-1
Continuous Synthesis of Glycerol Acetates in SC-CO2 Using SiO2-
SO3H
31
Flow rate= 1.1 mL.min-1
Molar ratio= 24
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.50
20
40
60
80
100
Yield% TA DA
Time / h
Sele
ctiv
ity o
r Y
ield
/ %
% Selectivity and Yield of the Reaction at different CO2 Flow Rates and Molar Ratio of 24 vs.Time Using Silica Sulfuric Acid as Catalyst
0.0 1.0 2.0 3.0 4.00
20
40
60
80
100
Yield % TA DA
Time / h
Sele
ctiv
ity o
r Y
ield
/ %
Flow rate= 1.5 mL.min-1
Molar ratio= 24
32
Flow rate= 1.1 mL.min-1
Molar ratio= 30
0.0 1.0 2.0 3.0 4.0 5.00
20
40
60
80
100
Yield% TA% DA%
Time / hSe
lect
ivity
ot Y
ield
/ %
% Selectivity and Yield of the Reaction at different CO2 Flow Rates and Molar Ratio of 30 vs. Time Using Silica Sulfuric Acid as Catalyst
Flow rate= 2.0 mL.min-1
Molar ratio= 30
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.00
20
40
60
80
100
TA DA Yield
Time / h
Sele
ctiv
ity o
r Y
ield
/ %
33
% Selectivity and Yield of the Reaction at different CO2 Flow Rates and Molar Ratio of 30 vs. Time Using Silica
Sulfuric Acid as Catalyst at Pressure of 250 bar
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.00
20
40
60
80
100
Yield TA DA
Time / h
Sele
ctiv
ity o
r Y
ield
/ %
34
Zeolite HZSM-5 (x)
35
Continuous Synthesis of Glycerol Acetates in SCCO2 Using H-ZSM-
5(x) T = 110 °C P = 200 bar Molar ratio = 24 1 g catalyst was dispersed within crushed glass (~12 g) Catalyst bed = 9 mm i. d., 15 cm long
Catalyst Conversion (%) Yield (%) TA (%) DA (%) MA (%)H-ZSM-5(30) 75 31 0 2 97H-ZSM-5(170) 92 51 0 8 92
36
Catalyst Conversion (%) Yield (%) TA (%) DA (%) MA (%)H-ZSM-5(80) 57 43 0 0 100H-ZSM-5(120) 100 43 0 0 100
0 50 100 150 200 2500
20
40
60
80
100
MA Conversion% Yield%
Time / min
Sele
ctiv
ity o
r Y
ield
or
Con
vers
ion
/ %
Catalyst bed: 4 mm (i. d.), 25 cm (length)
37
Ionic liquid Methyl Imidazolium Hydrogen Sulfate
NN
HH3C
HSO4
38
Continuous Synthesis of Glycerol Acetates in SC-CO2 Using Methyl Imidazolium HSO4
⊝
T = 110 °C P = 200 bar Molar ratio = 24 and 30 Catalyst dispersed on SiO2
Catalyst bed = 4 mm i. d., 25 cm long
39
0 50 100 150 2000
20
40
60
80
100
DA Yield% MA
Time / min
Sele
ctiv
ity o
r Y
ield
/ %
Methyl Imidazolium Hydrogen Sulfate (20%)
40
0 50 100 150 2000
20
40
60
80
100
DA Yield
Time / min
Sele
ctiv
ity o
r Y
ield
/ %
Methyl Imidazolium Hydrogen Sulfate (30%)
41
0 50 100 150 2000
20
40
60
80
100
DA Yield
Time / min
Sele
ctiv
ity o
r Y
ield
/ %
Methyl Imidazolium Hydrogen Sulfate (20%)
42
Pressure The molar ratio of acetic acid to glycerol CO2 flow rate Substrates flow rate TA synthesized selectively (100%) MA synthesized selectively(100%) MA synthesized selectively (<100%) DA Synthesized selectively (100%)
• Gly.• AcOH
-H2O
Conclusion:
Without Catalyst
H-ZSM-5(x) [x= 30 , 170]
IL , Methyl imidazolium [HSO4]
43
Selective extraction of TA from a mixture of TA, DA, and MA with the composition of 1:2:1 molar
Separation of Glycerol acetate
44
Semi-continuous SFE
%Y = (wext/w0) × 100Extraction yield (Y):
Selectivity (S): S = (YA/YB)
The standard mixture of TA, DA and MA ( 1:2:1)
45
Central Composite Design (CCD)
exxbxbxbbY ji
ji
i jij
k
iiii
k
iii
1
2
10
Variables Low level (-1) Medium level (0) High level (+1)
P (bar) 100 120 140
T (oC) 48 60 72
f (mL·min-1)a 0.5 0.8 1.1
t (min) 30 45 70a Liquid CO2 flow rate at 60 bar and 0°C.
Range of selected levels for four variables in the semi-continuous SFE process
46
0 20 40 60 80 1000
20
40
60
80
100
R² = 0.965317385558961
Experimental values / %
Pred
icte
d va
lues
/ %
0 20 40 60 80 1000
20
40
60
80
100
f(x) = 1.04018292672914 x − 4.32649469029693R² = 0.93638795721442
Experimental values /%
Pred
icte
d va
lues
/ %
P = 140 barT = 48 °Cf = 1.1 mL·min-1
t = 60 min
TA = 95.6%DA = 96.9%
The maximum extraction yield
47
Term%DA %TA
Coefficient t-value p-value Coefficient t-value p-value
Constant 128.401 1.269 0.224 -157.482 -1.388 0.185
P (bar) -1.180 -1.046 0.312 1.885 1.490 0.157
T (°C) -1.448 -0.969 0.348 0.520 -0.310 0.761
f (mL·min-1) -45.396 -0.855 0.406 48.278 0.811 0.430
t (min) -0.848 -0.788 0.443 2.300 1.905 0.076
P2 (bar)2 0.012 2.754 0.015 -0.013 -2.689 0.017
T2 (°C)2 0.048 5.328 0.000 -0.016 -1.557 0.140
f2 (mL·min-1)2 2.579 0.179 0.860 -26.138 -1.619 0.126
t (min)2 -0.001 -0.239 0.814 -0.010 -1.551 0.142
P (bar)*T (°C) -0.037 -5.147 0.000 0.020 2.569 0.021
P (bar)*f (mL·min-1) 1.057 3.714 0.002 0.780 2.443 0.027
P (bar)*t (min) 0.015 2.711 0.016 0.005 0.842 0.413
T (°C)*f (mL·min-1) -1.043 -2.198 0.044 -0.689 -1.295 0.215
T (°C)*t (min) -0.009 -0.978 0.343 -0.018 -1.707 0.108
f (mL·min-1)*t (min) 0.134 0.345 0.728 -0.387 -0.910 0.377
Regression coefficients, t-test, and significance p-values for the model estimated by Minitab software.
48
P = 109 barT = 56 °C f = 0.86 mL·min-1
t = 61 min
Response Optimizer Tools
TA =62%DA=17%
49
80
0
50
80 100 120 14080 100100 120120
100
150
0.5160
1.00.5
1.5
P (bar)
f (mL/min)
% DA
-50
50
35 45 55 65 7535
-50
45
0
50
5555
50
100
50
100
10075 80
8580
160140120
10080
160
T (°C)
P (bar)
% T A
800
50
80 100 120 14080 100 120120
100
0.5160
1.00.5
1.5
f (mL/min)
P (bar)
% TA
80
0
50
80 100 120 14080 100100 120120
100
150
0.5160
1.00.5
1.5
P (bar)
f (mL/min)
% DA
(a)
(b)
Response Surface Plots of DA and TA % Extraction Yield
f = 0.86 mL.min-1
t = 61.0 min
T = 56.0 °Ct = 61.0 min
50
40 50 60 70 8080
90
100
110
120
130
140
150
160
T (°C)
P (b
ar)
10
95
(a)
8070605040
160
150
140
130
120
110
100
90
80
T(°C)
P (b
ar)
10
100
(b)
DA
TA
Practicable Region of The DA and TA % Extraction Yield
f = 0.86 mL.min-1 t = 61.0 min
51
Continuous –SCF Fractionation
56 °C
70 °C The standard mixture:TA, DA , MA( 1:2:1)
52
Experimental matrix for a 2×3 general factorial design and experimental data obtained for continuous scCO2 fractionation.
RunP
(bar)
f
(mL/min)
Feed
(g)
Extracted
(g)
Compound extracted(g) Recovery a
Sc
TA DA MA TA DA MA
1 140 0.86 7.137 0.650 0.5740 0.0800 N.D.b 28.69 2.24 0.00 18
2 140 1.5 7.020 0.889 0.8224 0.1072 N.D. 41.79 3.05 0.00 23
3 100 1.5 7.020 0.130 0.0890 0.0305 0.0050 4.52 0.87 0.33 5
4 109 1.5 7.371 0.288 0.2242 0.0508 N.D. 10.85 1.38 0.00 9
5 109 0.86 7.020 0.124 0.1042 0.0233 N.D. 5.29 0.66 0.00 8
6 100 0.86 7.254 0.093 0.0607 0.0220 0.0039 2.98 0.61 0.25 5a Recovery is the weight percent of recovered compound by scCO2 to the original weight % in the feed.b N.D. = No MA was detected at this conditions.c S is the selectivity defined as the weight % of TA to DA in the extract.
53
100
109 140
0.86
1.50
50
60
70
50
60
70Pressure
Flow rate
100
109
140
0.86
1.50
(b)
1.50
0.86
140
109100
22
17
1222
17
12
Pressure
Flow rate1.50
0.86
140
109
100
(a)
The interaction plots for the continuous supercritical fluid fractionation set up:
DA
TA
54
Continuous –SCF Fractionation
45 °C
85 °C TA (8.9 %)DA (4.9 %)AcOH (86 %)
70 °C
55
Raffinate (%) Extracted (%) Variabls
RunMA DA TA AcOH DA TA AcOHF
(mL.min-
1)
T(°C)
P(bar)
0.00 6.50 10.07 85.17 1.80 2.08 73.37 1 45 70 1
0.00 5.94 10.33 82.32 8/76 4.31 87.37 1.5 45 70 2
0.00 5.97 10.43 81.84 2.59 1.97 98.99 1 70 70 3
0.00 7.74 12.99 78.13 0.00 0.00 103.19 1.5 70 70 4
0.00 7.01 13.54 84.58 0.00 1.03 114.79 1 45 100 5
0.00 10.54 17.83 70.45 0.00 1.65 101.28 1.5 45 100 6
0.00 7.45 12.76 83.27 0.00 0.79 127.87 1 70 100 7
2.27 17.33 22.15 53.20 0.00 3.60 97.72 1.5 70 100 8
2.14 13.88 8.76 88.17 0.00 1.47 110.31 1 45 100 9
2.70 15.36 20.04 61.15 0.00 3.71 101.94 1.5 45 120 10
0.00 13.55 22.46 72.47 0.00 1.06 106.85 1 70 120 11
2.04 19.51 21.73 50.31 0.00 4.84 100.06 5/1 70 120 12
0.00 12.14 13.25 69.02 1.06 5.80 94.17 1 45 140 13
0.00 14.73 10.57 67.80 1.61 9.20 94.10 1.5 45 140 14
0.00 14.13 14.87 72.91 0.00 5.95 102.94 1 70 140 15
2.14 17.7 11.88 64.17 1.52 7.64 94.12 1.5 70 140 16
Experimental matrix for a 2×4×2 general factorial design and experimental data obtained for continuous scCO2 fractionation
56
The interaction plots for the continuous supercritical fluid fractionation set up:
Raffinate
Extract
57
?TA
DAMA
Conclusion: Removal of MA from the mixture of TA, DA and MA using a
semi-continuous SFE. Prediction of the best condition toward TA 100% extraction
selectively. A mixture of 31.50 and 19 (w/w %) 62% of TA & 17%
of DA. Continuous fractionation process 41.8% of TA & 3.0%
DA. Continuous fractionation process for selective extraction of AcOH
from the esterification product.
58
Removal of produced water by using proper azeotrope. Catalyst screening towards the synthesis of TA, DA, and MA
selectively. Variation of packing and column size towards selective extraction of
TA. Reduction of pressure and/or temperature for extracting excess
AcOH from the esterification products before entering into packed column.
On-line Continuous synthesis and separation of glycerol acetate Using SCF technology to convert glycerol to the other valuable
products.
Recommendations
59
I WOULD LIKE TO THANK