INDIAN J. CHEM., VOL. 17A, MARCH 1979

COO.

B _ ~ ~o = ~ - o·!'»If ~ ~(OH)COOII + {llO)2c>:C10-PTIf (2)

I ,/ "'OH Cl OR

~(OB)COOH last) RCOCOOH + If

COOS

II _ ~ .!O'- ~ - 0- PfIl+ .1OW) BCOCOOS+ ~.clO- P1\I+ W• ~) O'lJ'cl

step. The hydride transfer may take place directly(Scheme 1) or may involve prior iormation of achromate ester (Scheme 2). There is no kineticevidence for the initial formation of a chromateester. However, in chromic acid oxidations, whichshow similar kinetics, ester formation is well estab-lishedv-". Thus one cannot ignore the possibilityof initial ester formation. The present data do notenable to distinguish between the two mechanisms.

References1. COREY, E. J. & SUGGS, W. J., Tetrahedron Lett., (1975),

2647.2. BANERJI, K. K., Z. Naturforscb., 28B (1973), 450.3. PERRIN, D. D., ARMAREGO, W. L. & PERRIN, D. R.,

Purification of organic compounds (Pergamon Press,Oxfcrd), 1966.

4. FEIGL, F., Spot tests in organic analysis (Elsevier,Amsterdam). 1966, 482. .

5. MITCHELL (Jr). J., Organic analysis, Vol. I (Irrterscience,New York), 1953, 271. . .

6. WIBERG, K. B., Oxidation in organic chemistry; Part A(Academic Press, New York), 1965, 69.

7. RAO, C. N. R., A handbook of physics and chemistry(Affiliated Press, New Delhi). 1967, 169.

8. AMIS, E. S., Solvent effects on reaction rates and mecha-nisms (Academic Press, New York). 1967, 42.

9. BAKORE, G. V. & NARAIN, S., J. chem, Soc., (1963), 3419.10. WIBERG, K. B. & SCHAFER, H., J. Am. chem, Soc., 91

(1969). 933.

Kinetics of Molybdate-catalysed Epoxidation ofAllyl Chloride by Hydrogen Peroxide

IFTIKHAR AHMAD* & C. MUHAMMAD ASHRAFDepartment of Chemistry, Makerere University

P.O. Bcx 7062, Kampala, Uganda

Received lOA pril 1978; accepted 9 June 1978

The kinetics of molybdate catalysed epoxidation ofallyl chloride in ethanol-water mixture by hydrogenperoxide have been reported. The reaction is first ordereach with respect to allyl chlor-ide and molybdic acidand zero order with respect to hydrogen peroxide con-centration. A reaction mechanism has been proposed.

EPOXIDATION of olefins with hydrogen per-oxide in the presence of some oxy compounds

of transition metals has been investigated by manyworkers':". Recently, Beg and Ahmadv" reportedthe kinetics of tungstate- or molybdate-catalysedepoxidation of C(,~-unsaturated acids by hydrogenperoxide. In this note, kinetics of molybdic acid-catalysed epoxidation of allyl chloride in ethanol-water mixture by hydrogen peroxide is reported.

The kinetic studies were made as reportedearlier", The presence of epoxide in the reactionproduct was indicated by the positive reaction

302

(

,with picric acid and confirmed colorimetrically".The reaction rate was determined as a function ofconcentration of hydrogen peroxide, allyl chloride,molybdic acid and hydrogen ions. The concen-tration of hydrogen peroxide was kept low as com-pared to that of allyl chloride such that for anysingle run the concentration of allyl chloride wasconstant. Under these conditions, the rate showsfirst order dependence on the concentration of-each of allyl chloride and molybdic acid and isindependent of hydrogen peroxide concentration.Pseudo-zero order rates are reported here as kObS

(Table 1).The molybdate-catalysed epoxidation rate of

allyl chloride increases with the increase in pH andis maximum at the pH at which [HMoO;jJ is maxi-mum, and thereafter the rate as well as [HMoO;j]decreases with further increase in pH (Table 2).This suggests that peroxymolybdic acid anion isinvolved in epoxidation. The probable epoxida-tion mechanism is shown in Scheme 1.

k,

H2Mo04~HMo04 + H+HMoO;j + H202--7 HMoOs + H20

k,CH2=CH-CH2Cl+HMo05~Intermediate

s.,

... (1)

... (2)

complex ... (3)k,

Intermediate complex-e-Cl-lj- - - -CH-CH2Cl+"'0/

HMo04 ... (4)Scheme 1

TABLE 1 - EpOXIDATION OF ALLYL CHLORIDE BYHYDROGEN PEROXIDE USING MOLYBDIC ACID AS CATALYST

(PH = 4·4; temp. ~ 28°)

[1'[202] xl 03

(M)

3·154·215·266·315·265·265·265'265'265·265·265'265·26

[H2MoO.lX 103(M)

2·002·002·002·001'501·002·503'003·502·002'002·002'00

kobsxl03

mol litre-I min-l[Allyl chloride]

xl02(M)

7'897·897·897·897·897897·897·897·893·955·92

11'8415'78

1·331·351·331·360·980·681·672·033·350·671·011·342'72

TABLE 2 -- DEPENDENCE OF EpOXIDATION RATE OFALLYL CHLORIDE ON THE pH OF THE MEDIUM

{[H2021 = 5·26xl0-3M; [allyl chloride] = 7'89xl0-2M;[H2MoO.l = 2'00 X 10-3M; temp., 28°}

pH kobs X le3(mol litre-I min-I)

0·701·241·351·311'29

z-s3·94·45·26·3

Assuming steady state for the concentration ofthe intermediate complex, the following epoxidationrate is obtainedEpoxidation rate =

k3k4[CH2= CH -CH20H] [HMoO",](k_3+k4)

An increase in ionic strength (from 3·1 x i0-3Mto 12·5 X 10-3M by the addition of NaCl04) did notaffect the rate.

References1. MUGDAN,M. & YOUNG,D. P., J. chem, Soc., (1949), 2988.2. PAYNE, G. & WILLIAMS,P., .T. org. Chern., 24 (1959), 54.3. ALLAN,G. G. & NEOGI,A. N., J. Catalysis, 19 (1970), 256.4. BEG, M. A. & AHMAD,T., J. Catalysis, 39 (1975), 260.5. BEG, M. A. & AHMAD,T., Indian]. Chem., 15A (1977), 105.6. FIORITI, A., BENTZ, A. P. & SIMS, R. J., J. Am. Oil

Chem. Soc., 43 (1966), 37.

Complexes of N,N'-Ethylenebis(N-phenylthio-urea) with Cu(lI) Chloride, Bromide, Nitrate,

Sulphate & Perchlorate

K. C. SATPATHY*,H. P. MISHRA& T. D. MAHANAP.G. Department of Chemistry, Sambalpur University

Jyoti Vihar, Burla ?68017

Received 20 April 1978; revised 5 August 1978;accepted 10 November 1978

Uopper(II) complexes of the type, [CuL]Xn [whereL = 1,2-di(phenyl thiourea N'-yl)ethane and X = CI-,Br", NO;, CIO;j and 801-; n = 2 or 1] have been prepared.The molar conductances suggest the complexes to beelectrolytic in nature. Probable structures of thecomplexes have been proposed based on elementalanalysis, magnetic moments, electronic and IR spectraldata.

METAL complexes of quadridentate chelatingagents containing both sulphur and nitrogen

donor atoms such as 1,8-bis(2'-pyridyl)-3,6-dithio-ctane, I ,6-bis(2' -pyridyl)-2,5-dithiahexane, 1,2-di-(0' -aminothiophenoxy) ethane, and 1,4-di-(0-amino-thiophenoxy)but-trans-2-ene have been investigatedby earlier workers-:". We report in this note thesynthesis and structure elucidation of chelat es of1,2-di(phenylthiourea N2-yl)ethane5 (DPTUE) with

NOTES

copper(II) chloride, bromide, nitrate, perchlorate andsulphate.

1,2-Di(phenylthiourea W-yl)ethane (DPTUE) wasprepared by literature methods, m.p. 174° (lit.5m.p. 174°).

The ligand and the appropriate copper(II) saltwere taken in equimolar proportions in ethanol,refluxed on a water-bath for 1 hr, filtered and thefiltrate allowed to evaporate slowly. A colouredsolid that separated out was filtered, washed, driedand analysed (Table 1). The chelates are quitestable at room temperature and fairly soluble inwater. The complexes are soluble in polar solventslike water, acetone and ethanol and conductivitymeasurements show them to be electrolytic in nature.

The ligand can be structurally represented bystructures (I), (II) or (III). However, the importantfeatures of the IR spectrum] of the ligand in KErprovide evidence in favour of structure (I). Theligand shows four bands at 3420, 3280; 2960, 2890.The former pair of bands are strong and sharpand can be assigned to vNH stretching vibra.tionst"and the latter pair to vCH of ethylene linkage andphenyl groups!". The existence of two NH bandsis due to different NH groups. Further evidencein support of structure I is indicated by theabsence of any S- H band for the ligand in theregion 2600-2400 (ref. 11).

The spectra of all the complexes prepared in thisstudy show only one broad band around 3320,which can be assigned to vNH. This band isrelatively broader than either of the original vNHof the ligand. This clearly implies that one of theNH groups is coordinated to the metal ion and

S\I

CH. - NH - c - NHPhICH. - NH - C - NHPh

. ~

SHI

CH.-N = C-NHPhI

CH. - N = C - NHPhISH

IISHI

CH.-NH-C = NPhICH.-NH-C = NPh

ISH

III

TABLE 1 - ANALYTICALDATAOF COPPER(II)

Formula Colour

[Cu(DPTUE)]Cl. Light red

[Cu(DPTUE)] Br. Bluish grey

[Cu(DPTUE)] (N03). Yellowish green

[Cu(DPTUE)] (CI04). Brown

[Cu(DPTUE)] S04 do

COMPLEXESOF 1,2-DI(PHENYLTHIOUREAN"YL)ETHANE

iJ.eff in B.M. Found (%) (Calc.)(28°±1°)

Metal S N1·77 13-80 13'94 12'65

(13-68) (13-80) (12'05)1·80 11'85 11'59 10·64

(11'48) (11'52) (10'12)1'81 12·12 11·71 15·82

(12'28) (12'39) (16'22)1·80 10'00 10·83 10·83

(10'72) (.10'80) (9'45)1·95 12'63 12'95 10·98

(12'97) (13'08) (11-03)

tIR vmas through<;JUtthe paper in crn'",

,..

(

303

-,\\