Solvent Extraction with Quaternary Ammonium Halides


Model 162 scaler was used. Contacting Apparatus. ... Distribution Ratio of Various Quaternary Ammonium Halides, Given a. Log D,. HC1. Hyamine. Tetra- ...
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Values for total furfural concentration of the test solutions, calculated by Equation 8, are listed in the last column of Table I. These have a relative standard deviation of k1.587, and a standard deviation, when compared to the average value calculated from the intercept, of =k1.62y0. DISCUSSION

The procedure described may be used for the determination of furfural in the presence of bisulfite ion. Such solutions are frequently encountered when working with sulfite pulping liquors, but the method should be of much greater usefulness, as it can be used to obtain quantitative information on many of

the aldehyde-bisulfite equilibria. Such systems are encountered frequently and, in general, little information is available. Equilibrium measurements may be made by adding small, known quantities of furfural and determining the absorbance of the resulting solutions. From these measurements, the free bisulfite ion in the solutions may be obtained. The furfural is thus employed as a n indicator of bisulfite ion concentration. When used in this manner, the method should be useful for solving many problems. LITERATURE CITED

Miller, F. A,, in Gilman, H., “Organic Chemietry,” Vol. 111, 1st ed., p. 167,

(1)

Wiley, New York, !953:

( 2 ) Root, D. F., “Kinetics of the AcidCatalyzed Conversion of Xylose to

Furfural,” unpublished Ph.I>. thesis, Chemical Engineering Department, University of Wisconsin, 1956. (3) Root, D. F., Saeman, J. F., Harris, J. F., Keill, W. K., Forest Products J . 9, 1.58 f l%W\. , - - - - I

(4)-Sheppard, W. A., Bourns, A. N., Can. J . Chem. 32, 4 (1954). (5) Shriner, R. L., Land, A. H., J . Org. Chem. 6, 888 (1941). (6) Stewart, T. D., Donnally, L. J., J . Am. Chem. SOC.54, 2333, 3555 (1932). f7) Tomoda. Y.. J . SOC. Chem. Ind. ’ (Japan)30, 747 (1927). RECEIVEDfor review August 10, 1961. Accepted November 6, 1961. Study supported in part by Sonoco Products CO., Hartsville, N. C.

Solvent Extraction with Quaternary Ammonium Halides ARTHUR M. WILSON, LILLIAN CHURCHILL, KENNETH KILUK, and PAUL HOVSEPIAN Chemistry Department, Wayne State University, Detroit 2, Mich.

b The solvent extraction of metal ions b y quaternary ammonium halides dissolved in 1,2-dichIoroethane i s described. The extraction i s dependent upon the ion association of the quaternary ammonium ion with labile chloro anionic complexes of Fe(lll), Co(ll), Zn(ll), and TI(III) or with the oxyanions o f Hf(lV), Ta(V), and Mo(VI) in concentrated hydrochloric acid or lithium chloride. The effects o f metal ion concentration, contacting time, and type of quaternary ammonium halide are investigated with the cobalt ion. Extractions o f >soy0 for cobalt are possible only if the distribution ratio of the quaternary ammonium halide itself i s very large. The value of the distribution ratio of the cobalt ion i s dependent upon the quaternary ammonium ions’ size, shape, and type o f organic groups. An analogy between solvent extraction with quaternary ammonium halides and anion exchange of metal ions in concentrated hydrochloric acid is demonstrated.

I

RECENT YEARS, many solvent extraction systems have been described which utilized high molecular \\-eight amines. General review of this field have been written by Coleman et al. (4), Moore (IS), and Morrison and Freiser (14). I n general, metal anionic complexes and simple and complex oxyanionic metals and nonmetals have been extracted from acidic aqueous media. The following paragraph, quoted from Moore’s review (13), is an excellent N

the same general form (17) that Kraus et al. (9) observed with Dowex 1; thus, many investigators have drawn a formal analogy and called liquid “Smith and Page (19) first reported extractions with high molecular weight that the acid-binding properties of amines “liquid anion exchangers.” high molecular weight amines depend If the extraction mechanism is ion on the fact that acid salts of these association to produce neutral species, bases are, in general, essentially init is reasonable that high molecular soluble in water but readily soluble in weight quaternary ammonium halides organic solvents, such as chloroform, benzene, or kerosine. The extraction should be more efficient as liquid anion reactions are of the following ionexchangers. I n fact, they should be association type: operative even us. basic aqueous media, 1. The organic solvent containing as Katekaru and Freiser (8) have the amine can extract an aqueous acid demonstrated with the extraction of to form an amine salt in the organic the anionic tris(8-hydroxyquinolinato) phase : complex of calcium(I1) a t p H 12.2(R3S)o Ha+ A , - S ( R I N H - ~ - ] ~ 12.9 into methyl isobutyl ketone. Other authors have used quaternary where RBN = 3 high molecular weight ammonium compounds to charge-neuamine tralize anionic metal complexes and A = an anion of either a simple acid or a complex hence enhance the percentage of metal metal acid, like FeC14extracted. Clifford et al. (3) have o = organic phase utilized Arquad 2C-75 (a 75% solua = aqueousphase tion in isopropyl alcohol of dialkylI n alkaline solution, the extraction is dimethylammonium chloride where each reversed. of the two alkyl groups has 8 to 18 2 . An amine sult in the organic carbon atoms, averaging about 16 phase can undergo anion exchange with carbon atoms) to charge-neutralize the an ion in the aqupous phase: anionic 8-quinolinol complex of uranyl (RaNH+A-)o Ba-CRJJH+B-).+ A,ion to extract it more efficiently into methyl isobutyl ketone. Maeck et al. The order of preference in the amine organic solution is similar to that in (11) have utilized tetrapropylammoanion exchange resins : nium nitrate to charge-neutralize the anionic trinitrate complex of uranyl C10,- > ?io$-> C1- > HSO4- > F-(4).” ion for extraction into methyl isobutyl ketone. Since less polar solvents than This exchange of the chlorometal commethyl isobutyl ketone can extract plex anions for the simple anion apuranyl complexes-viz., uranyl nitrate parently occurs a t the interface and into pentaether (16) and uranyl quinoproduces distribution ratio us. hydrolinolate into chloroform (It?), it is chloric acid molarity curves which have

explanation of the mechanism of distributions with high molecular weight amines.

+

+

+

VOL. 34, NO. 2, FEBRUARY 1962

203

reasonable to expect t h a t the uranyl nitrate and quinolinolate would extract to a small extent into methyl isobutyl ketone in the absence of a quaternary ammonium halide. The purpose of this a o r k is to investigate a series of commercially available quaternary ammonium halides to find out what structural configurations produce optimum extractions with a model system, the anionic cobalt(I1) complexes; to show that there is a minimum carbon content necessary in the quaternary ammonium head for a favorable extraction to be obtained-i.e., per cent extraction 250, into 1,2-dichloroethane, a solvent which will not permit the extraction of simple inorganic complexes of cobalt; and, to demonstrate that quaternary ammonium halides can be considered strong liquid anion exchangers by studying several metal ions in hydrochloric acid media and drawing an analogy with the work of Kraus et al. (9) using Dowex 1 in hydrochloric acid media. APPARATUS

Radioactivity Determinations. Since all tracer-carrier solutions were gamma emitters, the activity of either phase was determined by counting in a well of a X.R.D. Model L-6 scintillation counter. -4 Nuclear Corp. Model 162 scaler was used. Contacting Apparatus. All equilibrations were obtained by contacting the two phases in a stoppered 40-ml. borosilicate or Teflon centrifuge tube on a specially constructed 2-foot wheel which inverted t h e tubes 128 times per minute. This provides a gentle action which does not produce emulsions. I n all distribution studies, at least 3-minute contact times were used unless noted otherwise. Phase separation was effected by centrifugation a t 2600 r.p.m. for 10 minutes in an International Model CAI centrifuge. REAGENTS

1,2 - Dichloroethane. Baker and Adamson technical grade lJ2-dichloroethane was shaken with sulfuric acid, washed with distilled mater, and distilled from phosphorus pentoxide a t

82' to 83' C., according to the procedure of Fieser ( 5 ) . Supporting Electrolytes. All aqueous supporting electrolyte solutions were prepared from commercially available reagent grade chemicals without further purification. Concentrated solutions were assayed for the desired anion, and more dilute solutions were obtained by withdrawing appropriate aliquots. Halide containing solutions n-ere assayed by gravimetric silver halide procedures. Sitrite \\as assayed by a permanganate titration, and thiocyanate was assayed by an argentometric titration with ferric thiocyanate indicator. Disodium dihydrogen (ethylenedinitrilo) tetraacetate dihydrate (Matheson, Coleman and B~11Co., c. P. rcagents) purified according to 13laedt.l and Knight (2) \T-as taken as a primary standard. Quarternary Ammonium Compounds. All solid quaternary ammonium halides were dried a t 110' C., unless this treatment resulted in decomposition, in which case, they \T ere dried in a vacuum desiccator a t room temperature. One tenth molar solutions in 1,2-dichloroethane Fere prepared from the appropriate weight of these dried samples. The sources of these compounds Tvere as follows: Hyamine 1622 monohydrate and tetradecyldimethylbenzylammonium chloride, Rohm 8t Haas Co., Philadelphia, Pa. ; trimethylphenylammonium iodide, tetramethylammonium chloride, tetrabutylammonium bromide, tetraheptylammonium iodide, and hexadecyltrimethylammonium bromide, Eastman Kodak Co., Rochester, 9.Y. (Eastman White Label, except the hexadecyltrime thylammonium bromide) ; Arquad 2 HT-75 (a mixture of 24% dihexadecyl, 75% dioctadecyl, and 1% dioctadecenyl-dimethylammoniumchloride, dissolved 75y0 by weight in isopropyl alcohol) , Armour Industrial Chemical Co., Chicago, Ill. Solutions of ilrquad 2 HT-75, O . l J 1 , were prepared by dissolving the appropriate aliquot in purified 1,Z-dichloroethane. Tracer-Carrier Metal Ion Solutions. Tracer-carrier solutions containing approximately 106 gamma counts per minute per ml. and 10-2J1 of the metal

Table I. Distribution Ratio of Various Quaternary Ammonium Halides, Given a Log D,

HCl

Concn., M 0.10 1 .o 6.0 12.2

204

Hyamine 1622 3.6 4.3 4.2 3.9

Tetraheptylammonium Iodide

ANALYTICAL CHEMISTRY

4.4 4.6 5.0 5.0

Arquad 2HT-75 4.6 4.6 4.0 4.5

Tetrabutylammonium Bromide

Hexadecyltrimethylammonium Chloride

-4.2 -3.3 -4.1 -3.2

-4.5 -3.5 -4.4 -3.4

with enough hydrochloric acid to prevent hydrolysis were prepared to study the distributions of these metal ions in hydrochloric acid solutions. Cobalt. Cobalt metal (F. IT. Kerr Co.) and 5.2-year C060 tracer. Iron. Electrolytic iron (Fisher) and 45-day Fe59 tracer. Zinc. Zinc metal (J. T. Baker Co.) and 245-day Zn65 tracer. Hafnium. HfOCl2.8H2O (Atomic Energy Commission, Oak Ridge Laboratory, 99.9% HfOC12.8H20) and 46day I-If181 tracer. Tantalum. K2TaF7 (Eimer and Amend Co. c. P. grade) and I l l - d a y Tal82 tracer. AIolybdenuni. The 67-hour A I 0 9 9 is 0.1111 in (SH4)2AIoO4 carrier as received from Oak Ridge. This stock was diluted 1000-fold for distribution studies. Thallium. A 0.01M carrier-106 count's per niinute per ml. of 4-year Tl?04n-as transformed int'o the T1C13 form by fusing an appropriate n-eight of TlCl (P.AIacKny Co.) and 50 X 106 counts per niinute of T1204in sodium peroxide, dissolving in concent'rated HCl, and extracting the soluble portion into ether. The ether layer IT-as e\-:iporat,ed t o dryness, and the residue n-as dissolved in 50 nil. of 12.131 IICI. PROCEDURES A N D RESULTS

Determination of Distribution Ratios of Quaternaries. The procedure of Metcalfe (12) n a s used to determine the concentration of quaternary ammonium ion in either the aqueous or 1,2-dichloroetliane phase. The method is based upon the extraction of the sulfopthalein indicator, bromophenol blue, from an acidic aqueous solution of the indicator by ion association IT ith the quaternary aninionium ion in a chloroforni layer. The association is assumed to be stoichiometric. The blue color of the basic form of the indicator is developed by contacting the quaternary aninionium-indicatorchloroform phase Kith an aqueous 1% sodium carbonate solution. The absorbance ivas measured a t 605 nip with a Bausch & Lonib Spectroiiic 20 spectrophotometer after drying the chloroform phase over calcium chloride. h calibration curve was constructed because Beer's law was not obeyed. The distribution ratio is calculated by material balance consideration>. Three milliliters of 0.100-11 quaternary animonium halide in the lJ2-dicholoroethane phase is contacted with 3 ml. of the hydrochloric acid phase, ranging in concentration from 0.100 to 12.2111. The phases are separated and an appropriate-sized aliquot is 17 ithdrawn and the quaternary ammonium ion concentration, [&+I, is determined by measuring the color development from the more dilute phase. Since the original concentration of quaternary ammonium ion is known, the concentration of the other phase is determined by dif-

ference. The value of the distribution ratio is given as:

D, =

[&+lo/[&+].

The average results of duplicate determinations are summarized in Table I. Since the high molecular weight quaternary ammoniuin halides are surface-active agents, emulsions are formed when the quaternary ammonium halide is present a t 0.100M in either phase if the supporting electrolyte in the aqueous phase drops below a critical concentration. An electrolyte concentration equal to or greater than the quaternary ammonium halide concentration prevents emulsion formation. The organic phase was initially 0.lOOJI with regard to the quaternary ammonium halide in all results of Table I. To be certain that equilibrium values were obtained in the cases where the quaternary ammonium halide strongly favors the organic phase, a n additional experiment was performed with the Hyamiiie 1622 system. I n this experiment, the I-Iyamine 1622 n-as placed initially in the aqueous phase. The results are identical with those obtained where Hyamine 1622 was placed originally in the organic phase. Determination of Distribution Ratios of Metal Ions. At least 10,000 counts w r e taken on a n appropriate aliquot of each phaqe. Background was subtracted and the d a t a were then evpressed as counts per minute

per nil. for each phase. Equal volumes, usually 10 ml., of both phases were contacted. There was no change in volumes after contacting. The counts per minute per ml. are proportional to the concentration of all species in each phase, and the value of the distribution ratio, D,, is given as: D,

=

(counts/niin./ml.) (counts/min./ml.) a

For values of D , of 1 to 20, the precision of D , is estimated to be 1 3 % . The precision falls off sharply as D, increases because of low-counting values for the aqueous phase. At the limit of this technique, where D , = 103, the \ d u e may be in error as much as 2070. The aierage value of at least duplicate determinations of D , is reported. The effect of metal concentration on D , n a s obtained by placing varying rolunies of either the cobalt tracercarrier solution or varying volumes of pure tracer cobalt in a hydrochloric acid solution, final molarity 9.0, and contacting against 0.10.11 Hj-amine 1622 in 1,2-dichloroethane. Results are summarized in Table 11. Effect of Anion Concentration on Cobalt (11) Distribution. The results of Table I1 indicate t h a t equilibrium values for D , are obtained with 3minute contacting if t h e carrier level is set a t 10-4X. Thus, these conditions mere chosen to study the effect 0)

4

3

2

I

a 01

3 0

-I

-2

-3

0

4

8

12

Molar Figure 1 . Effect of various ligands on cobalt(l1) distribution into 0.1 OOM Hyamine 1622-1,2-dichloroethane-electrolyte: C)-NH,SCN, x-NaNO1, V-LiBr, A-HBr, 0-LiCI, *HCI

Table II. Dependence of Cobalt(l1) Distribution Ratio on Concentration and Contact Time

Cobalt (11) concen-

Contact Time, Minutes

tration, Jf

3

10-3 10-4

1.23 1.23 1.20 1.00

io-5

10-6

15 Log Dm '

30

, . .

1.22

1.23 1.23 1.23

...

...

Cobalt (11)

Tracer Volume (PI.) 500 100 50 25 10 5

1.23 1.23 1.23 1.14 1.09 0.99

1.23 1.23 1.23 1.23 1.23 1.23

... ... ...

...

various anions on the distribution of cobalt into O.lOJ1 Hyaniine 16221,2-dichloroethane phases. Results are summarized in Figure 1. blank deterniination n-as run in n-hich the distribution of colialt from a 9.0-11 hydrochloric acid media into pure 1,2dichloroethane TI-as measured. The value of log D,,, for this quaternary blank was -2.60. Thus, the solvent conditions are most unfavorable for distribution of a metal ion in the absence of a quaternary in 1,2-dichloroethane . Thr distribution of 10-4.11 cohalt(I1) into 0.10.11 Hyamine 1622-lJ2-dichloroethane from 10-331 etlij-lenedinitrilotetraacetate media was studied. With a 3.031 ammonium hydroside-ammonium nitrate buffer of pH 10.6,the value of D , v a s 0.50. TTheii the p H n-cts raised to 12 with a 0.01J1 sodium hydroside huffer, the value of D,, was 1.10. Effect of Various Quaternary Ammonium Halides on Cobalt(I1) Distribution Ratio. T h e follon-ing procedure \vas used t,o determine t h e effect of various types of quiternary aninionium halides on the distribution of cobalt(I1). The aqueous phase contained initially l O - 4 X cobalt(I1) carrier, l o 4 counts per minute per ml. of C060 tracer. and varying concentrations of hydrochloric acid. I n addition, the aqueous phase contained 0.100.11 quaternary ammonium halide if i t was not soluble to this extent in the organic phase. If the quaternary ammonium halide was soluble in 1,2-dichloroethanr, it was made 0.10031 in this phase. Contacting of the phases was carried out for 3 minutes. The phases were separated, and D, was determined as above. Since the same general shape of cobalt distribution vs. hyVOL. 34, NO. 2, FEBRUARY 1962

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drochloric acid molarity T T ~ found S for all quaternary ammonium halides studied, the results are summarized in Table 111 in the form of the distribution ratio of the maximum in the curve with a tabulation of the molarity of hydrochloric acid a t n-hich the maximum occurs. The Distribution of Various Metals in the 0.100M Hyamine 1622-1,2Dichloroethane-Hydrochloric Acid and Lithium Chloride System. Results in Table I11 indicate t h a t Hyamine 1622 does not yield D, values as large as tetraheptylammonium iodide or tetradecyldimethylbenzylaminoniuni chloride when cobalt (11) is t h e distributing ion. HolTever, tetraheptylammonium iodide cannot be dried Ttithout decomposition a t 100' C., nor is it photochemically stable. Also, tetradecyldimethylbenzylammonium chloride is not commercially available in the 100% pure form. Thus, Hyainine 1622 was chosen as the model quaternary ammonium halide for these studies. The results of distribution ratio determinations us. various molar concentrations of hydrochloric acid and lithium chloride are summarized in Figure 2 . X carrier level of 10-4X and a contact time of 3 minutes were used throughout the experiments. The results are the average of at least duplicate determinations. DISCUSSION

OF

RESULTS

The results of Table I1 indicate that t h e distribution ratio of the chlorocobaltate(I1) complexes are independent of the cobalt concentration from 10-3M don-n t o tracer levels, if equilibrium is established. Thus. it can be assumed t h a t no polymeric species of the chlorocobaltate(I1) complexes are formed in the organic layer. X comparison of the results of Tables I and I11 leads to the following generalizations about solvent extraction of cobalt(I1) with these quaternary ammonium halides. The quaternary ammonium halides fall into two groups

Table 111.

(16). If the number of carbon atoms on the quaternary ammonium ion is equal to or greater than 24, the distribution coefficient of the quaternary ammonium halide, D,, in the presence of an excess of electrolyte nil1 be about 104. If the number of carbon atoms is equal to or less than 19, D , = If D, = 104, the distribution coefficient of the metal, D,,,, will be large if an anionic complex of the metal is formed. However, a low value for D, does not prohibit a t least a 50% distribution of the metal ion-eg., tetrabutylammonium bromide. If the carbon content of two quaternary ammonium halides is about the same, the distribution of the metal ion is effected better with short, bulky aliphatic groups than with one or more long slender groups-e.g., tetraheptylamiiioniuni iodide us. dioctadecyldimethylammonium chloride (Arquad 2 HT-75) or tetrabutylammonium bromide us. heladecyltrimethylammonium bromide. Finally, the substitution of a benzyl group for a n aliphatic group greatly enhances the extractive power of the quaternary-

Effect of Various Quaternary Ammonium Halides on Cobalt(ll1 Distribution Ratio No. of Maximum Carbons D, HC1, M Type of R Groups

Arquad 2 HT-75 Tetraheptylammonium I Hyamine 1622

Tetradecyldimethylbenzylanimonium C1 Hexadecyltrimethylammonium Br Tetrabutylammonium Br

Trimethylphenylammonium Ia Tetramethylammonium C1* Ammonium CP a Insoluble in 1.2-dichloroethane.

206

Figure 2. Distribution of various metals into 0.1 OOM Hyamine 1622-1,2-dichloroethane from H C I - O or LiCI--0

ANALYTICAL CHEMISTRY

34 28

26

24

19 16 9

4 0

6.0 26.0 19.0 23.0 0.1 1.o 0.0 0.0 0.0

8

7

9 8 8 8

...

... ...

e.g., tetradecyldimethylbenzylammonium chloride us. Arquad 2 HT-75. Although enough data have not been presented to m r r a n t quantitative discussion of the mechanism of solvent extraction with quaternary ammonium halides, some qualitative conclusions can be drawn from the characteristic distribution curves for cobalt(II), iron (111), zinc(II), and thallium(III), found in Figures 1 and 2. For these metals, the value of D, increases with ligand concentration due to the formation of a n extractable complex anion. hlthough there may be more than one extractable species, there is reason to believe from Lindenbaum's work (10) and Good's work (6, 7') on cobalt(I1) and iron(II1) with high molecular weight amines us. hydrochloric acid that there is one species m-hich is much more readily extracted than all other species. I n the case of iron(", the extraction increases continuously until it becomes 1 0 0 ~ owhen hydrochloric acid is 6.0M or higher. I n the case of cobalt(II), thallium(II1), and zinc(II), a maximum is e'uhibited at Q.OM, 5.OM, and 3.OM in hydrochloric acid, respectively, and the curves regress at higher hydrochloric acid concentrations. If lithium chloride is used instead of hydrochloric acid as the aqueous electrolyte, the distribution curves of cobalt(I1) and zinc(I1) do not exhibit this maximum and regression. The slight decrease in D, for zinc(I1) us. 28.0X lithium chloride is not real because some insoluble zinc(I1)-containing material was found at the interface at these concentrations of lithium chloride. Thus, it would appear that the regression in the distribution curves is caused b y the hy-

drogen ion and not the chloride ion.

A plausible explanation is t h a t the hydrogen ion competes more favorably than the quaternary ammonium ion for the anionic metal complex a t higher hydrochloric acid concentrations. These hydrogen-associated complex anions have their effective negative charge lowered by one or more depending upon the number of hydrogen ions 15 hich associate. These weak complex acid species can associate with fewer or no quaternary ammonium ions, and the organic solubility of the metal complex decreases; hence, the distribution ratio of the metal decreases. Further Li-ork is in progress on the quantitative explanation of this phenomenon. The distribution curves of hafnium (IV), tantalum(V) , and molybdenum (VI), although characteristic for the metal ions, will not be discussed because these metals form fairly complicated oxyanionic complexes even in concentrated hydrochloric acid. If one takes the concentration of the ligand, which gives 50% extraction, as a criterion of the stability of the various cobalt( 11) complexes, i t is apparent from Figure 1 t h a t the stability of the complexes is in the order SCN- > NOz- > Br- > C1-, which is in agreement with reported stability constants (1). The reason why the nitrocobaltate(11) complexes do not extract as well as the bromo- and chlorocobaltate(I1) complexes must be due to the high oxygen content of the complex. Thus, the nitrocobaltate(I1) complexes are more “water-like” and less soluble in the organic phase. A similar argument may explain why the very stable (ethy1ene)dinitrilotetraacetate complex of cobalt(I1) extracts as poorly as i t does.

A comparison of the characteristic curves of all the metals studied in this paper in Figure 2 with those studied by Kraus et al. (9) suggests t h a t the mechanism of distribution by solvent extraction with quaternary ammonium halides is similar to the mechanism of distribution by elution chromatography with anion exchange resins. Thus, quaternary ammonium halides can be called “liquid anion exchangers.” Also, qualitative predictions about separations in one system should apply to the other system. I n general, the values of D, are lower in solvent extraction than in anion exchange chromatography. This will require multiple contactings in solvent extraction and frequent back extractions to obtain quantitative separations; however, this should not prohibit solvent extraction by quaternary ammonium halides from becoming an analytically useful technique where large capacity is of paramount importance. ACKNOWLEDGMENT

A portion of this work was supported through Grant No. At-(11-1)-775 of the U. S. Atomic Energy Commission. Paul Hovsepian gratefully acknowledges fellowship aid under the Summer Fellowship Program of the National Science Foundation for the summer of 1960. LITERATURE CITED

(1) Bjerrum, J., Sillen, L. G., Schwartzenbach, G., “Stability Constants. Part 11. Inorganic Ligands,” pp. 39, 97, 112, The Chemical Society, London, 1958. (2) Blaedel, W. T., Knight, H. T., ANAL. CHEM.26, 741 (1954). (3) Clifford, W. E., Bullwinkel, E. P., hlcClaine, L. A., Noble, P., Jr., J. Am. Chem. SOC.80, 2959 (1958).

(4) Coleman, C. F., Brown, K. B., Moore, J. G., Crouse, D. J., Ind. Eng.Chem. 50, 1756 (1958). (5) Fieser, L. F., “Experiments in Organic Chemistry,” p. 288, Heath and Co., Boston, 1957. (6) Good, M. L., Bryan, S. E., Abstract, pp. 43N44?i, 138th Meeting, ACS, Kew York, September 1960. (7) Good, M . L., Bryan, S. E., J . Am. Chem. SOC.82, 5636 (1960). (8) Katekaru, J., Freiser, H., abstract, p. 14B, 138th Meeting, ACS, New York, September 1960. (9) Kraus, K. A., Nelson, F., “Anion Exchange Studies of the Fission Products,” Vol. 111, Proceedings of the International Conference on Peaceful Uses of Atomic Energy, Geneva, 1955, p. 113, U. S., New York, 1956. (10) Lindenbaum, S., “Liquid Ion Eschangers,” Gordon Research Conferences on Ion Exchange, Tilton, ?;. H., June 1961. (11) Maeck, K. J., Booman, G. L.9 Elliot, M. C., Rein, J. E., ANAL. CHERI.30, 1902 (1958). (12) Metcalfe, L. D., Ibzd., 32, 70 (1960). (13) Moore. F. L.. Bull. KAS-XS-3101. ‘ 6ffice of’ Technical Services, Depart: ment of Commerce, Washington 25, D. C., 1961. (14) Morrison, G. H., Freiser, H., “Solvent Extraction in Analytical Chemistry,” Wiley, Sew York, 195:. (15) $fusser, D. F., Krause, D. P., Smellie, R. H., Jr., U. S. Atomic Energy Comm. Rep., AECD-3907. (16) Rosen, RI. J., Goldsmith, H. -4., “Systematic Analysis of Surface-Active Agents,” p. 10, Interscience, Sew York, 1960. (17) Schindewolf, L.> Progrcss Report, p. 23, RIass. Inst. Tech. Lab. for Xuclear Science, Feb. 23, 1956. (18) Silverman, L., LIoudy, I., Hawley, D. W., A s 4 ~ CHEV. . 2 5 , 1369 (1953). (19) Smith, E. L., Page, J. E., J . SOC. Cheni. Ind. (London) 67, 18 (1948). RECEIVED for review June 5 , 1961. -4ccepted Sovember 13, 1961. 8th Anachem Conference, Detroit, Nich., October 1960.

Use of Manganese(ll1) for Spectrophotometric Determination of Ferrocyanide, Tin(ll), and Iron(ll) WAHID U. MALIK and MOHAMMAD AJMAL Department o f Chemistry, Aligarh Muslim University, Aligarh, India

b Investigations of the oxidimetry of Mn(lll) have revealed that manganic sulfate can be employed for determination of the ferrocyanide (0.000804to 0.00296M), tin(ll) (0.001 to 0.01 3M), and iron(ll) (0.001 to 0.0999M) by carrying out absorption measurements at 5 2 5 my (absorption maximum for manganic sulfate solution). Better results for the estimation of ferrocyanide are, however, obtained by working at 425 mp (absorption maximum for potassium ferricyanide). Nitrite, SUIfite, and iodide interfere with the determinations.

M

aspects of the chemistry of Mn(II1)-viz., the use of the reagent as an analytical oxidant, its complexes, the influence of foreign ions on its oxidation potential, etc.-have not been fully investigated and need a more systematic study. Ubbelohde (4) pointed toward its possible use a s a n analytical reagent in volumetric analysis. Recently Malik (2) studied the reaction between Mn(II1) and potassium ferrocyanide and ascertained the following: Mn(II1) oxidizes potassium ferrocyanide to potassium ferricyanide, the change being possible in view of ANY

the high oxidation potential ( - 1.51 volts) of the couple hIn+3 e Mnf2; in a dilute solution of potassium ferrocyanide a perceptible change in color (from colorless to yellow) is observed on the addition of manganic sulfate solution; mith concentrated solutions of the reactants the oxidation of potassium ferrocyanide t o the ferricyanide is followed by the mutual interaction between hln(II1) and the oxidized product, yielding a n insoluble complex of the composition : hfn( 1II)Fe (111) Cyg. These observations led us to in-

+

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