Kalyanaraman, S.

Khopkar, S. M.

English

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NOTES*Similar extractionbehaviouris noted in 0·25M HNOs.tExtraction only in HNOs'TABLE 1- PERCENTAGE EXTRACTION OF MERCURY, COPPER,BISMUTH, COBALT, MANGANESE, ZINC, CADMIUM ANDINDIUM WITH 3% TOA IN BENZENEMetalionHg*CuBiCoMnZnCdIntInitial[H2S04]M3-41-6333330·25MHNO.Extraction%~O~O8~3~3~1~~O1~DistributionratioD99·0000,0900·0310,0380·0100·0200·0104. WELCHER, F. J., The analytical uses of EDTA (VanNostrand, New York), 1961,164, 180..5. GAWALI, S. B. & SHINDE, V. M., SejJar. Sci., 9 (1974),451.6. VOGEL, A. I., A textbookof quantitativeinorganicanalysis(Longmans,Green,London), 433, 434, 442, 443, 444.SolventExtractionof GermaniumUsingTributylPhosphateS. KALYANARAMAN & S. M. KHOPKARDepartmentof Chemistry, Indian Institute of TechnologyBombay 400076Received7 March 1977;accepted31 March 1977and estimatedphotometrically5.Mercurywas ex-tractedqu.antitativelyinto amine,whereasBi, Coane.Mn wereextractedinto amineonly partially.The coextractedelementswere,however,removedfromtheorganicphaseby back-washingwithwater(2X 10ml) and determinedin theaqueousphasebystandardprocedures6.MercuryfromTOA phasewasfinally strippedand estimatedas describedin theworkingprocedure.Theaveragerecoveryofmercuryis 99'0±0,2%. From binarymixturesthe averagerecoveriesof Cu, Bi, Co and Mn are 98,7,99'5,99·0and 99·6%respectively.Mercury(5 mg) and indium (2·5 to 5 mg) areseparatedby extractingmercuryfrom0·25M HNOssolution as describedin the working procedure.Indium is retainedin the aqueousphaseand esti-mated".Separation of mercury,zinc aJtd cadmium- Mer-cury,zincandcadmium(5 mgeach)wereseparatedby extractingmercuryas describedin the workingprocedure.Tracesof Zn and Cd, cocxtractedbythe aminealong with Hg, wereback-washedbyshakingthe organicphasewith 3M H2SO" (3X 10ml). This wasaddedto aqueousphasecontainingZn and Cd. Mercuryfrom the organicphasewasstrippedand estimatedas describedearlier. Forthe separationof zinc and cadmiumthe combinedaqueousphasewasequilibratedwith 10 ml of ben-zeneto removetracesof TOA, the solutionevapo-rated almostto drynessand finally sufficientHClandNH" SCNwereaddedto maketheconcentrationrespectively0·25 and 5M in a total volumeof 10ml. This solutionwasthen extractedwith 10 mlof 5% TOA in benzeneto quantitativelyseparatezinc from cadmium. Tracesof Cd wereremovedfromtheorganicphaseby shakingthricewith 5 mlof 0·25M HCI and 5M NH"SCN solutionanddeter-minedin the combinedaqueousphasecomplexo-metrically6.Znfromtheorganicphasewasstrippedwith 1M aqueousammoniasolution (10 ml) anddeterminedcomplexometrically6.References1. MOORE, F. L., Separ.Sci., 7 (1972),505.2. SINGH, OMVIR & TANDON, S. R., Separ. Sci., 10 (1975),359.3. IRVING, H. M. N. H. & DAMODARAN, A. D., Analyt.chim.Acta, 53 (1971),277.Tributylphosphate(25%)in toluenehasbeenusedfor the solventextractionof germaniumfrom 3MhydrOChloricacidcontaining2M magnesiumchlorideasthesalting-outagent. Germaniumis back-washedfromtheorganicphasewithwater(2x10ml) andisdeterminedphotometricallyat 510om as its red-colouredcomplexwithphenylftuorone.Theprobablecompositionof theextractablespeciesis GeCl4.2TBP.At 3 to 4M hydrochloricacidconcentrationi addi-tionto 2M magnesiumchloride4M lithium chlorideand 3M aluminiumchlorideare equallyeftective.The period of equilibrationis just 2 min. Ger,:maniumis extractedandphotometricallydeterminedin 1000-toldexcessof otherionswhichareassociatedwithit inminerals.SEVERAL methodsfor the solvent extractionof germanium are known but extractionsinvolving carbon tetrachloride1was the mostfavouredmeth0d. However, this method suffersfrom interferencedueto fluorideandarsenic. Theextractionswerepossibleonly at high acidity andhighconcentrationsof germaniumwerenot extract-able.With cyclohexanone2asan extractantarsenic,vanadium,antimonvand zirconiuminterfere.Withtributylphosphates"theextractionwas incompleteevenat high acidstrengthandtherewassubstan-tial decrease(25%) in the volumeof the organicphase. Themethodproposedby usis rapid,simpleandselective. It is applicableat tracerconcentra-tion andaffordsclear-cutseparationin thepresenceof large numberof elements.The reagentsemployedwereTBP (b.p. 143-45°),phenylfluorone(0·02%solutionin methanol)andgumarabic (0·5% solution in hot water). The stocksolutionof germaniumwaspreparedby dissolving2·112 g of germaniumdioxidein minimumvolumeof O·lM sodiumhydroxide,acidifiedwith hydro-chloric acid and dilutedto 250 ml with distilledwater. The solutionwas standardizedgravimetri-cally' and found to contain 5·64-8 mg Ge/ml.Other ~olutionscontainingrequiredamountof Gewerepreparedby dilution of the stock solution.Procedure- An aliquotof the solution contain-ing 11·29[Jogof germaniumwasmade3M in hydro-chloric acid containing2M magnesiumchloridein a total volumeof 25 ml andwastransferredtoa separatoryfunnel,10lIll of 25%TBP in toluene1031INDIAN J. CHEM., VOL. 15A, NOVEMBER 19770·752·375·1100,2·077·117·90000,974·437·57000·430·791-172·9327·2347·640,671·282'9322·50002·3013·2200Distributionratioin)Be2+,Ca2+,Sr24, Ba2+,SO~-,NOs, C20~-,thiourea-, citrateS-, EDT A4-, CH.COO',malonate,tartrate-SNi3+,Cu2+Zn2+,C02+,Cd2+,Fe2+,Rb+, Cs+,Ass+,SCN-,PO:-Ir3+,F-Mn2+,Bis+,Ga'+, In'+, y3+,U6+TiH, Th4+, Pd2+,Pt4+, Os8+,vasCr'+, TI+, Rhs+,Au3+,Pbs+, SeO~-, TeO~->Rea:',Br-, I-Hg2+,Sn4+Ag+,Sb3+0·51·01·52·02·53·00,51·01'52·0-3·00,51·01·52·0-3·00·51·01·52·02-5-3·00'51·01·52,0·3·00·51·01-5-3·0Initial[HCI] xM7'55,03·02·52·01·00,500·25[TBP]=15% (0'54M)14·424·032·054·091·696·0[TBP]=25% (0·91M)0'5 15'2 0.441·0 28'0 0,971'5 41·2 1·752'0 84.0 13-122'5 94,0 39·153·0 100·0 00[TBP]=25% (0'91M) IN THEABSENCEOFSALTING-OUTAGENT0'5 6·0 0·151·0 8'8 0·241'5 12·0 0·34~O 14~ 0403·0 16,2 0·484·0 26·4 0·795,0 66·0 4·846·0 100·0 00[TBP]=40% (1·46M)21·234·054·090,0100·0[TBP]=50% (1'83M)23·248,867·2100·0[TBP]=60% (2·19M)28·064·075·2100·0[TBP]=75% (2'56M)45·274·076·0100·0[TBP]=100% (3-66M)48·084,0100·0TABLE 1 - DISTRIBUTIONRATIO ASA FUNCTION OFACIDITY[Ge=11'29I-Lg, 2M MgCI2]Extraction(%)TABLE 2- EFFECTOFDIVERSEIONS{Ge(IV)=11'29[.lg;3M HCI+2M MgCI2; 25% TBP-toluene}Tolerance Diverse ionslimit1 X 10s[.lg10·0wasa dedandthemixturewasshakenfor 2-3min.Thet '0 phaseswereallowedto settleandseparate.The queouslayer was withdrawn. Germaniumwass rippedfromtheTBP-toluenephaseby shakingit tw ce with 10 ml of water. To the aqueoussoluti'n 5 ml of gum arabic and 5 ml of 12Mhydr hloric acid were added. The solutionwasdilute. to 30 ml. After adding5 ml of phenyl-fluoro e, it was madeup to 50 ml. The solutionwas Howedto stand for about 30 min and theabsoranceof the red-colouredcomplexmeasuredsped ophotometricallyat 510 nm against thereaget blank5•Th resultsof preliminaryexperiments(Table I)to st dy the effectof varyingacidity and [1'BP]showthat for quantitativeextractionof germaniumit is onveniento use25% TBP in toluene.Theopti U111 hydrochloricacid concentrationwas 3Min t presenceof 2M magnesiumchloride. Anatte pt wasmadeto establishtheprobablecomposi-tion f the extractablespecies1'1yplotting log Dvers log [TBP] at 1·5 and 2M hydrochloricacid. The slopeswere1·73and 2·12respectively,indic tingthattheextractablespeciesto bedisolvat-ed a GeCI4.2TBP. Benzene,chloroform,carbontetrahloride and methyl isobutyl ketone beingthemelvesextractantsfor germaniumwereavoidedas t Ie diluents.Seeral salting-outagentssuch as chloridesofhthi , sodium,potassiummagnesium,and alumi-nium were tried. The results showedthat theextr tion of germaniumwas quantitativefrom3 to 4M hydrochloricacid, in the presenceofeithe 4M lithium chloride or 2M magnesiumchlorde or 3M aluminiumchlorideas the salting-out gent. For all practicalpurposes2M magne-sium chloridewas preferredas salting-outagentdue 0 small ionic concentrations.Th periodof equilibrationwasvariedfrom 1 to20mn. The resultsshowedthat 2 to 3 minequili-brati'n wasquiteadequatefor quantitativeextrac-tionof germanium.The period of equilibrationis co parablewith other extraction procedures2•Va ious ions weretestedfor interferencein theextr tion of germanium(Table2). The tolerancelimit was set as the amountof foreignion thatwoul cauSe ±2% error in the recovery ofgermnium. It was observed that germaniumwas extractedquantitativelyin the presenceofalkal, alkaline earth metals and commoncom-plexi g anions in 1000-foldexcessratio relativeto g rmanium. Zinc, cobalt,cadmium,iron, thio-cyan.te, phosphateand arsenicweretoleratedin500-fld excessratio Tin and antimony whichshowd someinterferencewereselectivelyextractedwith 8-hydroxyquinoline6at pH 2·5 and mesityloxid7 at 3M hydrochloricacid respectively.Theintererenceof silverandmercurywereeliminatedby electiveextractionwith thiothenoyltrifluoro-acetne8,9 at pH 1·0 and 2·5 respectively.Theions ikemanganese,nickel,cobalt,yttrium,iridium,alkal and alkaline earths and thorium are notextr ctable with diluted tributyl phosphateandhenc showno interference.The relativestandarddevi tion of the methodis ±0·35%.1032"1;.~II INOTESReferences1. DHOND, P. V. & KHOPKAR, S. M., Analyt. chim. Acta,59 (1972),161.2. KORKISCH,J. , Modern methodsfor theseparationof rarermetalions (PergamonPress, London), 1969,349.3. MAGUNOV',R. L., TURKALOV',N. F., ZAKOLODYAZHNA,O. V. & STASENKO,1. V., Khim. Prom., Inform. nauk.-tekh.zb., 2 (1965),29.4. VOGEL,A.!., A textbooko/quantitativeinorganicanalysis(Longmans,Green, London), 1964,653.5. SANDELL, E. B., Colorim/Jtricdeterminationof tracesofmetals(Interscience,New York), 1959,490.6. DE, A. K., KHOPKAR,S. M. & CHALMERS,R. A., Solventextractionof metals(Van Nostrand-Reinhold,London),1970,81.7. DHOND,P. V. & KHOPKAR,S. M., Separ. Sci., 8(1973),379.8. SOLANKE, K. R. & KHOPKAR, S. M., 'Mikrochim. Acta,(1976),41.9. SOLANKE,K. R. & KHOPKAR,S. M., Indian J. Chem.,11(1973),485..0-( 01:-2- Oxopropylbenzylideneimino)benzene-sulphonicAcid as a Gravimetric Reagentfor Co(I1),Ni(I1) & Cu(I1)B. R. SINGHV'I,D. C. SEHGAL& R. K. MEHTADepartmentof Chemistry, University of Jodhpur, JodhpurReceived5 February 1977;accepted22 May 1977o-(or.-2-Oxopropylbenzylideneimino)benzenesulpho-nic acid(H20B) hasbeenemployedas a gravimetricreagentfor theestimatiOnofCo(I1),Ni(I1)andCu(I1).Solid metalchelateshavealso beenisolatedwhichshow 1 : 1 (metal-ligand)stoichiometry.OctahedralstructureshavebeenassignedtothecomplexesonthebasisoftheirmagneticmomentsandIR spectra.HOLM etaU and others2-4have recently reviewedthe metalchelatesof Schiff bases.0-(0I:-2-0xopro-pylbenzylideneimino)benzenesulphonicacid, H20B,a biprotic tridentate ligand, forms solid metalchelates5with a numberof bivalent metal ions suchas Mn(Il), Fe(Il), Co(Il), Ni(Il), Cu(Il), Zn(Il),Cd(Il), Pd(Il), UO~+and V02+.Co(Il), Ni(Il) and Cu(Il) chelates are insolublein water and can thus form the basisof a procedurefor their quantitative separation.The reagent(H20B) wassynthesizedby the methodreported earlier6•7• A 10% solution of the reagentwas prepared in aq. ethanol for use in the gravi-metric determination of Co(II), Ni(Il) and Cu(Il).The stock solutions were prepared by dissolvingAR grade (BDH) cobalt(Il) nitrate, nickel(Il)sulphate and copper(Il) sulphate and their metalcontents were estimated bv standard methodsB•Procedure- The pH valuesfor the metal ion solu-tions were adjusted with suitable buffers between5·7 and 6·6 for Co(Il), 5·0 and 6·2 for Ni(Il) and3·7 and 4,5 for Cu(Il) solutions. The reagentwasgradually added to these solutions with constantstirring. Using ag. ammonia (2.M), the pH ofCo(Il), Ni(Il) and Cu(Il) solutions were raised to8,7, 8·2 and 7·5 respectively. Rich-cream, light-'green and water-greenprecipitatesof metalchelatesWere obtained in the case of Co(II), Ni(Il) andCu(Il) solutions respectively, which were heatedat 100-110° for 5-10min, cooledand filteredthroughweighedsintered glass crucibles. The precipitateswere free from the reagent by washing with aq.ethanol, filtered, dried at 100-105°and weighed.The results obtained are summarizedin Table 1.Estimation of Ni(II) and Cu(II) i·n the presenceof eachother- The pH of the solution containingNi(II) and Cu(Il) was adjusted between 3,7 and4,5 using sodium acetate (2%) solution and 1·5 gof ammonium thiocyanate was added graduallywith stirring. After heating at 75-80°,the reagentwas added,pH was raised to 7,5 with aq. ammonia(2M) whenCu(lI) chelateprecipitatedout. Finallythe solution was heated at 100-110°for 5 min,cooled, filtered, and the precipitate was washed,dried and weighed as described earlier. In thefiltrate the nickel thiocyanate was decomposedbyboiling it for 10 min after acidification with dil.HCI. Ni(Il) chelate was then precipitated as de-scribed earlier. Using this procedure both Cu(II)and Ni(II) can be accurately determined (±0·3%)when present together.Effect of foreign ions in the estimationof Ni(II)and Cu(II) - Fe3+ and V5+ were masked usingsodium potassium tartarate and TiH by potassiumfluoride in thesedeterminations. Anions like SO~-,PO~-,Cl- and F- did not interfere in the pH range7·5-8·2 but Co(Il) interefered as it also reactswith the reagent, therefore, the solutions must befree from COS-f'.On the basis of elemental analyses, molecularweight and magnetic moment data, the complexesmay be representedby the formula [M(C16H13NS04).(H20)3J where M=Co(II), Ni(II) or Cu(II). IRspectrumof the reagentshowsthree bands at 3600,1680and 1170cm-1which can be assignedto vOH,TABLE 1- RESULTSOFGRAV'IMETRICESTIMATIONOFCo(I1), Ni(I1) AND Cu(II)Metal (mg)TakenFoundError (%)Co(I1)46·9046·790·2337·7037 6140 350 2019 419 01Ni(II)3 73,8438 498 892 -5622 02 3CurTI)9 241·2111033

Solvent Extraction of Germanium Using Tributyl Phosphate

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Solvent Extraction of Germanium Using Tributyl Phosphate

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