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Chemical Engineering Science 54 (1999) 3967}3976

Uncatalysed oxidation of cyclohexene
S.M. Mahajani, M.M. Sharma, T. Sridhar*
Department of Chemical Engineering, Monash University, Clayton, Victoria 3168, Australia Received 13 October 1998; received in revised form 22 December 1998; accepted 23 December 1998

Abstract The oxidation products of cyclohexene "nd several applications as intermediates for the manufacture of useful chemicals like cyclohexanol, cyclohexenol/cyclohexenone, cyclohexadiene, etc. The uncatalysed oxidation of cyclohexene with molecular oxygen was studied in a batch reactor. The products, cyclohexene hydroperoxide, cyclohexenol, cyclohexenone and cyclohexene oxide were realised in the temperature range of 343}393 K. The e!ect of various kinetic parameters such as temperature, speed of agitation and wall material was studied. The kinetic data were generated at di!erent temperatures and "tted successfully with a rate equation based on autocatalysis by total products. The values of rate constants and activation energy were determined. Recognising the fact that the industrial route to cyclohexene from benzene hydrogenation yields a mixture of cyclohexene and cyclohexane which are di$cult to separate, some experiments on oxidation of the mixture of cyclohexene and cyclohexane were also conducted. The values of rate constants remain unchanged in the presence of cyclohexane. The reaction was also studied in an aluminium lined reactor to examine the wall catalytic e!ect, if any, of the stainless steel wall. The reaction was found to be signi"cantly slower in the aluminium reactor while the selectivity towards the hydroperoxide remained unchanged. The oxidation of cyclohexene represents a unique example of an 1999 Elsevier Science Ltd. uncatalysed liquid-phase organic oxidation which can be conducted up to relatively high conversions. Allrights reserved. Keywords: Cyclohexene; Cyclohexenyl hydroperoxide; Autoxidation; Cyclohexenone; Cyclohexenol;

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