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ORNL-TM-1480
Contract No. W-7^05-eng-26
ISOTOPES DEVELOPMENT CENTER
THE EXTRACTION OF TRIVALENT GOLD FROM HYDROCHLORIC ACIDSOLUTIONS INTO ISOPROPYL ETHER, BIS-(p-CHLOROETHYL)
ETHER, ETHYL ACETATE, AMYL ACETATE, AND METHYL ISOBUTYL KETONE
J. J. Pinajian
Isotopes Division
APRIL 1966
OAK RIDGE NATIONAL LABORATORY
Oak Ridge, Tennessee
operated byUNION CARBIDE CORPORATION
for the
U.S. ATOMIC ENERGY COMMISSION
OAK RIDGE NATIONAL LABORATORY LIBRARIES
3 ^st ostTmH t
Ill
CONTENTS
Page
Abstract !
Introduction 1
Procedure 2
Results 5
THE EXTRACTION OF TRIVALENT GOLD FROM HYDROCHLORIC ACIDSOLUTIONS INTO ISOPROPYL ETHER, BIS-(p-CHLOROETHYL)
ETHER, ETHYL ACETATE, AMYL ACETATE, AND METHYL ISOBUTYL KETONE
J. J. Pinajian
ABSTRACT
The extraction of trivalent gold by isopropyl ether,bis-(p-chloroethyl) ether, ethyl acetate, amyl acetate,and methyl isobutyl ketone from hydrochloric acid solutions was studied as a function of acid concentration.The distribution coefficients were found to decrease inthe order: amyl acetate < isopropyl ether < ethylacetate < bis-(p-chloroethyl) ether < methyl isobutylketone. Isopropyl ether and ethyl acetate were foundto be soluble in higher concentrations of hydrochloricacid solutions. Bis-(p-chloroethyl) ether has a distribution coefficient reaching a maximum of 495 at 6 MHC1. Methyl isobutyl ketone has a distribution coefficient of IO98 at 6 M HC1 which increases to ~6000 at1 M HC1. The distribution coefficient of platinum was
found to be ~10~2 at 6 M HC1 and factors for separationfrom gold were estimated to be 5 x 104, 5 x 103, and6 x 105 for isopropyl ether, bis-(p-chloroethyl) ether,and methyl isobutyl ketone, respectively.
INTRODUCTION
Solvent extraction procedures offer a convenient method for the separa
tion of micro-to-macro quantities of metals in comparatively simple steps.
Thus, the problem of separating carrier-free 195Au or 199Au from a platinum
target, for example, may be carried out efficiently using solvent extrac
tion, provided that the distribution coefficient of gold is sufficiently
greater than that of platinum. By judicious choice of an organic solvent/
aqueous system, carrier-free 195Au or 199Au may be prepared in a solids-free
state.
Since the literature offered little in the way of detailed information
on the extraction behavior of trivalent gold, we initiated a study of the
extraction of gold(lll) chloride in the hydrochloric acid system using
isopropyl ether, bis-(p-chloroethyl) ether, ethyl acetate, amyl acetate,
and methyl isobutyl ketone. Ethyl ether was not investigated because of
its volatility and flammability. The hydrochloric acid system was used
because it is more convenient to handle and has fewer undesirable features
for medical and biological applications and for the preparation of sources
for gamma-spectroscopy measurements.
PROCEDURE
The organic solvents used were standard stock reagents• No purifica
tion was undertaken since the procedures were designed for routine labora
tory operations.
Isopropyl ether, purified, Baker and Adamson, GeneralChemical Division, Allied Chemical Corporation
Bis-(p-chloroethyl) ether, Chemicals Division, UnionCarbide Corporation
Ethyl acetate, purified 95-93$> Baker and Adamson,General Chemical Division, Allied Chemical Corporation
Amyl acetate, purified, Baker and Adamson, GeneralChemical Division, Allied Chemical Corporation
Methyl isobutyl ketone (4-methyl-2-pentanone), B.P. ll4-ll6°C,Matheson, Coleman, and Bell, Division of MathesonCompany, Inc.
All aqueous solutions were prepared with demineralized water
(l-l x 106-ohm resistance).
In each case the solution of gold activity was evaporated down to
incipient dryness and then taken up in the desired acid concentration.
Care was taken not to use prolong heating while the gold activity was
at incipient dryness, since nitric acid would then be required to remove
the activity from the glass.
The gold activity used as the radioindicator was either 64.8-hr
198AuCl3, 1 M in HC1 and HN03, or 183-day l95AuCl3, 1 M in HC1. The
198Au activity was obtained from the Isotopes Sales Department, Oak Ridge
National Laboratory, and had a specific activity of 38.4 mc/mg gold. The
carrier-free l95Au activity was prepared by the proton irradiation of
platinum in the ORNL 86-Inch Cyclotron.1 Approximately 200 uc of activity
was used in each experiment.
The distribution data were obtained by contacting equal volumes (20 ml]
of the organic phase with the hydrochloric acid solutions containing the
l95Au- or l98Au-labeled gold. In each case, the organic was equilibrated,
prior to use, with the same concentration of hydrochloric acid used in
the study. Extractions were made at room temperature (22°C). Preliminary
experiments established the equilibrium time at <30 seconds. After con
tacting the two phases for O.5-I min, the phases were separated and centri-
fuged, and 1.00-ml aliquots taken for analysis- The analysis for the
l98Au was made by counting the 0.4l2-Mev photopeak, and for the 195Au, the
0.099-Mev photopeak, using a 3- by 3-in. Nal(Tl) gamma spectrometer.
Distribution data were also obtained in the same fashion for 3-4 mM
and 8.3 mM platinum, labeled with 3.0-day 191Pt.
RESULTS
The results of the distribution study are shown in the following
table. Figure 1 shows the distribution coefficient* of trivalent gold
in various organic solvents as a function of the hydrochloric acid con
centration.
*The distribution coefficient, KD, is defined as:
gold activity in the organic phaseD ~ gold activity in the aqueous phase
Table 1. Distribution Coefficients of Au3+ BetweenOrganic Solvents and Hydrochloric Acid Solutions
Au3+,mM
Distribution coefficients
Hydrochloric acid coneentration
Organic solvent 1 M 2 M 4 M 6 M 8 M 10 M
Isopropyl ether 0.0125 0-7 1-3 3-4 5.8 8.3b 0.3813
Bis-(p-chloroethyl)ether 0.0125 -- 279 4ll 495 408 4o6
Ethyl acetate CFa -- 46.2 23-8 9-1 — —
Amyl acetate CFa --0.43 0-37 0.33 — —
Methyl isobutyl ketone 0.0125 6038 3715 833 IO98 -- --
Carrier-free.
Organic solvent dissolves in aqueous phase•
Using the standard deviation of the ratios of the respective counting
rates (with their respective standard deviations) as an index of the reli
ability of the distribution data, then the following generalizations can be
made regarding the accuracy of the KD:
Range of Kp Estimated limit of error in data, jo
io3-io4 +100 -50
ic^-io3 +100 -50
101-102 +20 -10
1 -10 +10 -5
10_1-1 +10 -5
10~2-10-1 +20 -10
io"3-io-2 +100 -50
The increase in the extraction efficiency of bis-(p-chloroethyl) ether
over isopropyl ether follows the trend in the extraction behavior predicted
by Kuznetsov2 in his paper on the extraction of iron chloride into organic
10*ORNL-DWG 66-3117
103
<02
*D
10<
10°
-110
J98Au, 12.5x10~3 mMMETHYL ISOBUTYL KETONE
J98Au, 12.5X10"3 n\M/>/5-(/3-CHL0R0ETHYL) ETHER
J95Au, CARRIER-FREEETHYL ACETATE
i?5Au, CARRIER-FREEAMYL ACETATE
-498Au, 1.27x10-3 m/l/ISOPROPYL ETHER
6
HCI (M)
8 40
Fig. 1. The Distribution Coefficient of Trivalent Gold inVarious Organic Solvents as a Function of the Hydrochloric AcidConcentration.
12
solvents. The marked increase (by an order of magnitude) of the distri
bution coefficient with methyl isobutyl ketone again follows the trend
suggested by Kuznetsov. On the other hand, extraction with amyl acetate
is a factor of 100 less efficient than extraction with ethyl acetate.
There appears to be no question that bis-k(p-chloroethyl) ether and
methyl isobutyl ketone are far superior to the other solvents examined
for the extraction of gold(lll) chloride. The solubility of both isopropyl
ether and ethyl acetate in the acid solution restricts their effectiveness
as an extractant for gold.
These results also indicate that the distribution coefficient of
methyl isobutyl ketone increases markedly with a decrease in acid con
centration. The extraction of gold(lll) chloride with bis-(f3-chloroethyl)
ether, on the other hand, reaches a maximum at ~6 M HCl and then decreases
with a decrease in acid concentration.
The distribution coefficient for platinum was found to be ~10-2 for
bis-(p-chloroethyl) ether, ethyl acetate, and methyl isobutyl ketone.
Hence, factors for the separation of gold from platinum are 5 x 104,
5 x 103, and 6 x 105 for bis(p-chloroethyl)ether, ethyl acetate, and
methyl isobutyl ketone, respectively.
ACKNOWLEDGEMENTS
The author would like to thank A. P. Callahan for conducting these
experiments.
REFERENCES
1. J. J. Pinajian, The cyclotron preparation of carrier-free l95Au by
the l95Pt(p,n)l95Au + l96Pt(p,2n)l95Au reactions, to be published.
2. V. I. Kuznetsov, Ob izvlechenii organicheskimii rastvoritelyami
khlornogo zheleze iz solyanokislykh rastvorov, Zh. Obshch. Khim.
17: 175-80 (1947), [see S. J. Rimshaw and J. J. Pinajian, The
extraction of iron chloride from hydrochloric acid solutions by
organic solvents, USAEC Translation ORNL-tr-1199, Oak Ridge
National Laboratory (March 1966)].
•J
1.
2.
3<4-6.
1-8.
9-10.
11.
12.
13.14.
15.
56.57-58.59-60.
61.
62.
63.64.
65-67.68.
69.70.
71-
72.
73.74.75.
76.77-78.79-80.
81.
82.
83.84.
85.86,
87.
90.
91-92.
93.94-108.
P. S. Baker
E . E. Beauchamp
G. E. BoydT. A. Butler
F. N. Case
L. T. Corbin
J. A. Cox
J. H. Gillette
C P. Keim
M. T. Kelley
E. H. Kobisk
E. Lamb
L. 0. Love
/^
INTERNAL DISTRIBUTION
16. W. S. Lyon17. H. G. MacPherson
18-42. J. J. Pinajian43. M. E. Ramsey44. R. A. Robinson
45. A. F. Rupp46. F. G. Seeley47. A. M. Weinberg48. J. C White49. Laboratory Records — RC
5O-51. Central Research Library52-54. Laboratory Records
55. Document Reference Section
EXTERNAL DISTRIBUTION
Argonne National Laboratory, Argonne, Illinois0. M. Bizzell, Div. of Isotopes Development, AEC, Washington, D. CJ. L. Bloom, Div. of Isotopes Development, AEC, Washington, D. CR. E. Bowman, Div. of Technical Information, AEC, Washington, D. CE. J. Brunenkant, Div. of Technical Information, AEC, Washington, D. CH. D. Bruner, Div. of Biology and Medicine, AEC, Washington, D. CL. P. Bupp, General Electric Co., HAPO, Richland, WashingtonJ. T. Cristy, AEC-R00, Richland, WashingtonD. C Davis, Research and Development Div., AEC-ORO, Oak Ridge, Tenn.E. E. Fowler, Div. of Isotopes Development, AEC, Washington, D. C.R. N. Goslin, Dept. of Physics, Oglethorpe Univ., Atlanta, Ga.W. J. Haubach, Mound Laboratory, Miamisburg, OhioJ. W. Hitch, Div. of Isotopes Development, AEC, Washington, D. C1. A. Hobbs, AEC-SR00, Aiken, S. CJ. W. Irvine, 6-426, MIT, Cambridge 39, Mass.T. R. Jones, Div. of Research, AEC, Washington, D. C.B. F. Judson, General Electric Co., HAPO, Richland, WashingtonW. K. Kern, Div. of Isotopes Development, AEC, Washington, D. CG. A. Kolstad, Div. of Research, AEC, Washington, D. C.P. W. McDaniel, Div. of Research, AEC, Washington, D. C.J. E. Machurek, Div- of Isotopes Development, AEC, Washington, D. CB. Manowitz, Brookhaven National Lab., Upton, L. I., N. Y.R. B. Martin, Research and Development Div., AEC-ORO, Oak Ridge, Tenn.J. W. Morris, Savannah River Lab., E. I. duPont, Aiken, S. C.Mound Laboratory, Miamisburg, OhioF. K. Pittman, Div. of Reactor Development, AEC, Washington, D. CJ. A. Powers, Div. of Isotopes Development, AEC, Washington, D. C.G. L. Rogosa, Div. of Research, AEC, Washington, D. CG. J. Rotariu, Div- of Isotopes Development, AEC, Washington, D. CH. M. Roth, Research and Development Div., AEC-ORO, Oak Ridge, Tenn-L. G. Stang, Hot Lab. Div-, Brookhaven National Lab., Upton, L. I., N.Y.V. R. Thayer, Atomic Energy Division, E. I. duPont, Wilmington, Del.J. Vanderryn, Office of the General Manager, AEC, Washington, D. CLibrary, Brookhaven National Laboratory, Upton, L. I., N. Y.Library, Hanford Atomic Products Operation, Richland, WashingtonLibrary, Savannah River Laboratory, Aiken, S. C.DTIE, AEC