Reddy, G. Siva

Reddy, Y. Krishna

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INDIAN J. CHEM., VOL. 1SA, APRIL 1977Precipitation ofManganese Ammonium Phosphate fromHomogeneous Solution by Urea HydrolysisG. SIVA REDDY & Y. KRISHNA REDDYDepartment of Chemistry, S. V. University, TirupatiReceived 20 July 1976; accepted 16 September 1976Manganese has been precipitated as manganeseammonium phosphate from homogeneous solution byraising the pH of an initially acid solution containingMn(II) and PO~- ions in the presence of ammoniumsulphate by urea hydrolysis. Microscopic measure-ments showed that the particles obtained by thismethod were more than 100 times bigger than thoseobtained by conventional procedure. A comparison ofhomogeneous and conventional methods has been madewith regard to the separation of manganese fromCu(II) and Ni(II).pRECIPITATIONS of manganese as sulphide-sand oxinate" from homogeneous solution werereported in literature. Buzagh-Gere and Erdey"reported precipitation of manganese ammoniumphosphate from homogeneous solution by decompos-ing metal-EDTA complex with hydrogen peroxide.The present investigation deals with the sameprecipitation by raising the pH through urea hydro-lysis.All the chemicals used were of BDH analar grade.A stock solution of Mn(II) sulphate (,,-,0'06M) wasprepared and standardized by the conventionalprocedure=.To an aliquot of a standard solution of Mn(IJ).ammonium sulphate solution (50 ml, 25%). ammc-nium dihydrogen phosphate solution (15 rnl, 10%)and urea (10 g) were added. The pH of the reactic nmixture was adjusted to 5·5 with IN sulphuric acidand the solution diluted to 150 ml. A glass rodwas placed and the beaker kept in a hot air ovenmaintained at 90-95° for 5 hr. The water lost dueto evaporation was made up occasionally by freshadditions of distilled water. The solution wasallowed to cool to room temperature and filteredthrough IG3 sintered crucible. The precipitatewas washed with 1% diammonium hydrogen phos-phate solution until free from sulphate and thenwith aq. ethanol (1: 1) to free it from phosphateions; dried for 1 hr at 100-105° and weighed asMnNH4P04·H20.Manganese in amounts ranging from 20-100 mgcould be conveniently determined by this procedureand the maximum error was within ± 0·5%. Fora set of ten measurements of 76.50 mg of manganese.the relative mean error and standard deviation werefound to be 0'25% and 0'02 mg respectively (Table 1).The amount of manganese remaining in the filtratewas 40 fLgonly as determined by spectrophotometricmethod=.The precipitate obtained from homogeneous solu-tion was more coarse and crystalline than thatobtained by conventional procedure. Crystal sizesof 200 particles from the representative sample weremeasured using microscope. The median values352were found out by extrapolating the graph of parti-cle size vs logarithm of cumulative number. Themaximum, minimum and median values of particlesizes obtained by homogeneous method were 3960,180 and 1188 {J. respectively whereas the ccrrc-sponding values obtained by ccnventional methodwere 33. 3 and 11·6 microns only. The crystalsobtained by Buzagh-Gere and Erdey procedure!were only of two order magnitude.In this procedure, the formation cf precipitatenuclei was clearly visible at pH 6,1-6,3. Since thesolution should be perfectly clear to produce biggercrystals''-", the initial pH was adjusted to 5·5. Aminimum of 10 g of urea, 10 ml of the reagent and4 hr of heating were found to be necessary for com-plete precipitaticn.Presence of ammonium salts in moderate concen-trations was found to be essential for completeprecipitatien and alro for producing crystallineprecipitate. Addition of ammonium chloride, bro-mide, sulphate and tartrates (up to 20 g) did notinterfere in the determination. In the presence ofcompounds such as acetate, oxalate and succinate,precipitation precess was delayed and the precipi-tate obtained was always amoi phous in nature.Presence of ammonium formate produced turbidityTABLE 1 - DETERMINATION OF MANGANESE AS MANGANESEAMMONIUM PHOSPHATEAmountof man-ganesetakenmgStandarddeviationmgMeanvalue ofmanganesefound for5 deter-minationsmg19'0.38'2.57·3.76'4*.112·019.1338'2.57'3.76·5.112·00.110·0.0'050·0*.0.03*For 10 determinations.TABLE 2 - COPRECIPITATJON OF COPPER AND NICKEL*Amountof man-ganesetakenmgManganese foundt (mg)Amountof metalion addedmgPFHS Conven-tional76'5.76'5.76'5.76'5.76·5.76'5.IN THE PRESENCE OF ADDED CuSO.20·0 76.4840·0 76'5.60·0 76'5.80·0 76'6.100·0 76'8,120·0 77'0176.5876'6.77·1.77·5.78·0.78'4.IN THE PRESENCE OF ADDED NICKEL AMMONIUM SULPHATE76'5.76'5.76·5.76'5.20·040·060·080·076'4876.76n'31ri-s;76'5.rr»,rm,78'2.*15 g of ammonium tartrate added for each determination.tMean of three determinations.in the beginning itself and nitrate resulted in lowervalues. Out of all the anions tested, sulphate wasfound to be the most suitable anion in thisprocedure. Cu(II) , Ni(II) and Fe(III) inter-fered in the determination. However, interferencedue to Cu(II) and Ni(II) up to 80 and 40 mg respec-tively could be minimized by masking with 15 g ofammonium tartrate. The results recorded in Table2 show the comparison between homcgeneous andconventional methods with regard to the separationfrom Cu(II) and Ni(II) using the masking agent.Five-fold excess of sodium and potassium did notinterfere in the determination.The authors wish to thank Prof. V. R. Krishnanfor his interest in the work. The financial supportof the UGC, New Delhi, is gratefully acknowledged.References1. FLASCHKA,H. & ABDINE,H., Chemist Analyst, 44 (1955), 8.2. PILZ, W., Mh. Chem., 84 (1953), 471.3. HIKIME,S. YOSHIDA,H. TAGA,M. & TAGUCHI,5., Talanta,19 (1972), 569.4. BuzAGH-GERE,E. & ERDEY,L., Talanta, 16 (1969), 1434.5. VOGEL,A. I., A text book of quantitative inorganic analysis(Elbs & Longmans, London), 1961, (a) 536, (b) 787.6. INGOLS, R. S. & MURRAY,P. E., Analyt. Chem., 21(1949), 525.7. BASHAR,A. & TOWNSHEND,A., Talanta, 13 (1966), 1123.Diamagnetic Susceptibilities of CompoundsContaining C-Cl BondsR. R. GUPTADepartment of Chemistry, University of RajasthanJaipur 4Received 3 August 1976; accepted 14 December 1976Magnetic susceptibilities of a number of compoundscontaining C-CI bonds have been calculated usingPascal's, Gallais and Labarres', and Haberditzl's bondsusceptibility data. While the values obtained usingPascal and, Gallais and Labbare's methods deviate toa great extent from the experimental values, valuesobtained using Haberditzl's method give good agree-ment.FRENCH and Trew! have reported that experi-mental diamagnetic susceptibilities of halogenderivatives of methane cliffer very much from thosecalculated using Pascal's atomic susceptibility data.In this note diamagnetic susceptibilities (XM) fora number of compounds containing C-Cl bondshave been calculated using Pascal and Gallais andLabbares' methods", The results are summarizedin Table 1. Difference between calculated (byPascal's or Gallais and Labbare's methods) and ex-perimental XM values is more than 1% in all thecases and in some cases it is as high as 17%. Insuch calculations all factors except bond-bondinteractions are dulv accounted for. The anomalousresults may thus b~ due to bond-bond interactionswhich do contribute to diamagnetism. XM valueshave been calculated using Haberditzl's bond sus-ceptibility data also and the results are summarizedin Table 1. In such calculations bond-bond interac-tions are duly accounted for. All the calculatedvalues agree with the experimental values withinNOTESTABLE1 - DIAMAGNETICSUSCEPTIBILITIESOF ORGANICCOMPOUNDSCONTAININGC-CI BONDSCompound Diamagnetic susceptibility-XM X (10-6)Experi- Calculated Calculatedmental" using Pascal, usingGallais Haberditzl'sand dataLabbare'sdataMethyl chloriden-Propyl chlorideMethylene dichlorideChloroformCarbon tetrachlorideEthylidene chloride1,1,2,2-TetrachloroethanePentachloroethaneHexachloroethaneIs iamvl chloride2-Chlo~opropylene32·0056·1046·6058·8066·8057·4287·4899·13112·8078·9247·8033·9556·7548·5064·2580·0061·1091-40107-15122·9080·7548·9532-1556·0546·9558·5566·9557·1086'9099·60112·2079·4548·05*Literature values.1%. Therefore, Haberditzl's wave-mechanicalmethod can be applied to calculate molecular dia-magnetism even for the compounds in which bond-bond interactions are significantly large. It canbe inferred that bond-bond interactions are of largemagnitude and contribute significantly to diamag-netism in compounds containing C-Cl bonds.Author expresses sincere thanks to Profs. R. C.Mehrotra, K. C. Joshi and J. N. Gaur for encourage-ment.References1. FRENCH,C. M. & TREW,V. C. G., Trans. Faradav Soc., 41(1945), 439. .2. PASCAL,P., GALLAIS,F. & LABBARE,J., C.r. hebd, SeancA cad. Sci. Paris, 256 (1963), 333.3. HABERDITZL,W., Chem. Abstr., 62 (1965), 15572C.Oxidation of Fluorenes byCeric Ammonium Nitrate - A Kinetic StudyS. NARASIMHAN& N. VENKATASUBRAMANIANDepartment of Chemistry, Vivekananda CollegeMadras 600004Received 18 October 1976; accepted 3 December 1976Oxidation of ftuorenes by ceric ammonium nitratein acetic acid-nitric acid medium exhibits a firstorder dependence on each reactant. The reactionobeys the Hammett relationship, but the reactionconstant p exhibits a direct dependence on the tem-perature. The magnitude of the isotope effect andthe above temperature dependence of p indicate twodifferent mechanistic pathways at 50° and 65°.IN the oxidaticn of cycloheptatriene-, ceric ammo-nium nitrate (CAN) attacks selectively the 'It-bondrather than the hydrcgen atoms of the activemethylene group. We repOlt another instance inthe oxidation of fluorenes, wherein a similar selecti-vity by CAN, dependent on temperature is encoun-tered.353

Precipitation of Manganese Ammonium Phosphate from Homogeneous Solution by Urea Hydrolysis

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Precipitation of Manganese Ammonium Phosphate from Homogeneous Solution by Urea Hydrolysis

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