Khosla, M. M. L.

Rao, S. P.

Sharma, R. C.

English

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to have the values: log K~ = 9'49 and log K~ = 2·30at 25° and O'lM NaCI04. These values are in goodagreement with those reported by Perrin", whoobtained the two PK values as PK (oc-COOH) = 2·31and PK (oc-NH2) = 9·66 at 20° and 1M KCl.The PH titrations reveal that in Hg(II)-oc-amino-butyrate system the solution remains clear through-out but in the Be(U) and Cd(Il) systems precipitationoc~urs at PH ,....,7·0 and .....,9'5, respectively. Calcu-lations for ji values have been done only up to thesePH values, before the precipitation starts.The formation curves (Fig. 1) of the metal chelatesshow that in all the Cases fi attains a maximum valueof ~ 2 and thus the formation of two chelates MLand !fL2 is indicated.From an analysis of the formation curves, it isclear that for these systems K1/K2 ratio are .-..10,hence their stepwise stability constants have beencomputed by correction term and successive approxi-mation methods. Results are presented in Table 1.flG values were calculated using the relation: flG =-RT In K, and these are also given in Table 1.References1. ALBERT, A., Biochem. J.. 47 (1950). 531.2. PERKINS, D. J., Biochem., J., 55 (1953), 649.3. PERRIN, D. D., J. chem, Soc., (1958), 3125; (1959), 290.4. RALEA, R. & POPA, A., Analete Stiint. Univ. A.I. Cuzo,I asii Sect. I, 6 (1960), 391.5. SHARMA, V. S., MATHUR, H. B. & BISWAS, A. B., J.tnorg, nucl. Chem., 26 (1964), 382.6. SHARMA, V. 5., MATHUR, H. B. & KULKARNI, P. S., Indian1. cse«; 3 (1965), 146.7. RAIu, E. V. & MATHUR, H. B., J. inorg, nucl. cu,«30 (1968), 2181. '8. MEYER, J. L. & BAUMAN, (Jr), J.E., J. chem, Engng Data15 (1970), 404. '9. GERGELY, A., MOJZES, J. & KASSAI BAZSA, Z. S., J.tnorg, nucl, Chem., 34 (1972), 1277.10. CALVIN, :.vI.& 'WILSON, K. \¥., J. Am. chein. Soc. 67(1945), 2003. '11. BJERRUM, l, Metal ammine formation in aqueous solu-iions, (Haase, Copenhagen), 1942.12. IRVING, H. & ROSSOTTI, H. S., J. chem. Soc., (1953) 3397'(1954), 2904. ' ,13. WELCHER, F. J., The analytical uses oj ethylene diamine tetra-acetic acid (D. Van Nostrand, New York), 1957, 161, 164.14. HILLEBRAND, W. F., LUNDELL, G. F. E., BRIGTT, H. A.& HOFF;\IAN, J. I., Applied inorganic analysis (JohnWiley & Sons, New York), 1953, 522.Solvent Extraction of Cd(II) with N-Butyl-aniline in Chloroform from a Mixture ofPotassium Iodide & Sulphuric AcidS. P. RAO, R. C. SHARMA & M. M. L. KHOSLA*Department of Chemistry, University of Jodhpur, JodhpurReceived 23 September 1975; accepted 12 February 1976Cadmium is quantitatively extracted with N-butyl-aniline in chloroform from a mixture of 0·5M potasstumiodide and 0'5M sulphuric acid. It is easily strippedfrom the organic phase with ammonia buffer (pH = 10)and determined complexometrically with EDTA using,PAR as indicator. Cadmium is separated from manycations and anions. Log-Jog plot of the distributioncoefficient versus concentration of amine indicates a 2 : 1limiting, mole ratio of amine to metal and the probableextracted species is (R2NH~)2CdIi-.=Defence Laboratory, Jodhpur.NOTESIN the present investigation N-butylaniline1 inchloroform is reported as a new analyticalextraction reagent for Cd(Il) from a mixture ofpotassium iodide and sulphuric acid. Cadmium(Il)is readily and quantitatively extracted from amixture of 0'5M potassium iodide and 0'5M sul-phuric acid.General procedure - A 0·1 M solution of Cd(lI)was prepared by dissolving the required amount ofcadmium nitrate in redistilled water and standardizedcomplexornetrically with EDTA using PAR as indi-cator.To an aliquot of solution containing up to 50 mgof Cd (II) was added enough quantity of 6Mfreshly prepared solution of potassium iodide. 4Msulphuric acid and water so that the solution had0·5.111potassium iodide and 0·5M sulphuric acid ina volume of 15 ml. The solution was stirred for1-2 min with a solution of N-butylaniline (0'7 g in10 ml chloroform). The chloroform layer wasseparated and the aqueous layer reextracted withN -butylaniline solution (10 ml). The organic layerswere combined and Cd(lI} stripped off fromthe organic phase by sl: aking for 2 min withammonia buffer (25 rnl, PH = 10). The aqueousphase separated, warmed and to this was added4-(2-J?yridylazo) resorcinol (PAR) indicator (0'1%,w lv 1Il water) and titrated slowly with standardEDTA till the colour changed from red to yellow.Cadmium(Il) could be easily extracted andseparated from many cations and most of thecommon anions did not interfere (Table 1).Antimony(III and V) was kept in solution in thepresence of tartaric acid. Aluminium(III) wasslightly extracted but in presence of citric acid itcaused no interference. Common anions such assulphate, chloride, citrate, phosphate, tartarate andfluoride did not interfere. Several binary syntheticsamples were analysed and the relative error wasfound to be ± 2·5%.The extraction is quantitative at aqueous toorganic phase ratio of 1 :1·5 and in the presence ofTABLE 1 - PERMISSIBLE AMOUNTS OF VARIOUS IONS INTHE EXTRACTION OF Cd(I1)[Cd (II) added 11·24 mg; 0·50M KI and 0'50M H2S04]Foreign ion Foreign ion Amount. (mg)1415514162530577100010001000250Amount(mg)5958100120110433030303032SO1414Co (II)Ni(I1)Hg{I1)Sb(III)aFe (II)Al(III)bCa(II)Sr{II)Mg(II)Cr(III)Zn(II).Ga(III)Ce(III)Pr(III)Nd(III)Gd(III)Rh{III)La(III)Er(I1I)Sc(III)Y{III)W(VI)aNb(V)aTa(V)aTartrateCitratePhosphateFluoride(a) In the presence of tartaric acid (1000 mg).(b) In the presence of citric acid (500 mg).819INDIAN J. CHEM., VOL. 14A, OCTOBER 1976Extraction of Pd(II)-Thiocyanate Complexwith Ethyl Acetate from Aqueous Phase,·5,-41·)1·21-1',00-90'8 42 = 2.2]0 19tIO 0'7.20,6O'S0-4()'J0,20·,0'0T-O r.i 1·2 1·3 •.4 T·S rs ,·7 ,·8 rslog CFig. 1 - Plot of log D versus log ClO'5M KI and 0'5M H2S04, Two 10 ml portionsof 7% extractant were sufficient to extract 50 m~of Cd.(II) and larger amounts could be dealt withby further extraction. Quantitative extraction wasachieved by equilibrating the aqueous and theorganic phase for 2 min in the temperature ranee15-40°. :-Nature of extracted species - The nature of prob-able e~tracted species was investigated by singleextractIOn. of fixed amount of Cd(II) with varyingconcentrat~o~s of N-butylaniline, while keeping theother conditions constant as given under the generalprocedure. The ratio of the aqueous to organicphas~.wds 1:1·5. The plot of log D (distributionco~f!iclent) versus log C (concentration of Nsbutyl-aniline) gave a slope of 2·21 (Fig. 1) indicating thatth~ .probable extracted species is H2CdI, 2N-butyl-aniline.The authors are thankful to Prof. R. C. Kapoor,Head, Department of Chemistry, University ofJodhpur, for providing laboratory facilities. Oneof the authors (R.C.S.) is also thankful to theauthorities of University of Jodhpur for providinguniversity scholarship.References1. KHOSLA, M. M. L., Analytical uses of o-mercaptobenzoicacid and solvent extraction Of metals Ph.D. thesis,University of Jodhpur, 1972. '820PRAPHULLA K. PARIA & SANTOSH K. MAJUMDARDepartment of Chemistry, North Bengal UniversityDarjeelingReceived 15 October 1975; accepted 17 February 1976Pd(II)-thiocyanate complex has been extracted withethyl acetate to the extent of 95 ± 2% from 2M HCI inthe presence of NH,Cl. The effects of acidity, ammo-nium thiocyanate concentration, saltlng-out agents(likeM~CII,or NH.CI), period of extraction and presenceof diverse ions on the extraction behaviour of Pd(II)have also been Investigated,NUMEROUS solvents have been used to extractPd(JI) from aqueous phase in its chloride,nitrate, t+iocvanate and iodide formsv+. Previouswork on the extraction of thiocyanate complex ofPd(IJ) from aqueous solution with tributyl phos-phate 'has carried out by De and Sen- and Berge.The present work shows that Pd(JI) thiocyanatecomplex can be extracted with ethyl acetate fromaq. phase. In its chloride, bromide or iodideforms, Pd(IJ) 'has not extracted at all with ethylacetate. The effect of acidity, salting out agents,reagent concentration, period of extraction andinterferences due to other cations and anions on theextraction behaviour is discussed.The chemicals used were of CP or AR grade.Ethyl acetate (BDH) was distilled before use. A2% aqueous solution of ammonium thiocyanatewas used for complex formation.A stock solution of palladium chloride wasprepared by dissolving 1 g of PdCl2 (JohnsonMatthey) in 1 ml cone. hydrochloric acid and dilutingto 250 ml with distilled water. The solution wasstandardized gravimetrically using dimethylgly-oxime? and was found to contain 2·53 mg of Pd(II)per ml.Procedure - Calculated amount of hydrochloricacid of known strength was added to an aliquotcontaining 12'65 mg of Pd(Il) to have the desiredacid concentration (2M) followed by the additionof aqueous ammonium thiocyanate solution (2%,2 ml) and volume made up to 20 ml with distilledwater. The aqueous solution thus prepared wasshaken with 10 ml of ethyl acetate for 10 min. Thetwo layers were allowed to separate and the organicphase separated. Palladium was back-extractedfrom the ethyl acetate phase by shaking for 10 minwith distilled water (3 X 15 ml). The aqueous ex:-tracts were combined and evaporated to dryness.The residue was then digested with perchloric acidto destroy ammonium thiocyanate and any otherorganic matter cooled, diluted with water and Pd(lI)estimated gravimetrically by dimethyl glyoxime.The extraction behaviour of Pd(Il) with ethylacetate was investigated with various concentrationsof hydrochloric acid (from 0·06 to 5M). Maximumextraction was 87% from 3M hydrochloric acid.Above 5M hydrochloric acid concentration theorganic phase was found to be miscible with theaqueous phase.

Solvent Extraction of Cd(II) with N-Butylaniline in Chloroform from a Mixture of Potassium Iodide & Sulphuric Acid

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Solvent Extraction of Cd(II) with N-Butylaniline in Chloroform from a Mixture of Potassium Iodide & Sulphuric Acid

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