General Topics
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$cult to separate, some experiments on oxidation of the mixture of cyclohexene and cyclohexane were also conducted. The values of rate constants remain unchanged in the presence of cyclohexane. The reaction was also studied in an aluminium lined reactor to examine the wall catalytic e!ect, if any, of the stainless steel wall. The reaction was found to be signi"cantly slower in the aluminium reactor while the selectivity towards the hydroperoxide remained unchanged. The oxidation of cyclohexene represents a unique example of an 1999 Elsevier Science Ltd. uncatalysed liquid-phase organic oxidation which can be conducted up to relatively high conversions. Allrights reserved. Keywords: Cyclohexene; Cyclohexenyl hydroperoxide; Autoxidation; Cyclohexenone; Cyclohexenol;
Uncatalysed oxidation of cyclohexene
S.M. Mahajani, M.M. Sharma, T. Sridhar*
Department of Chemical Engineering, Monash University, Clayton, Victoria 3168, Australia Received 13 October 1998; received in revised form 22 December 1998; accepted 23 December 1998
Abstract The oxidation products of cyclohexene "nd several applications as intermediates for the manufacture of useful chemicals like cyclohexanol, cyclohexenol/cyclohexenone, cyclohexadiene, etc. The uncatalysed oxidation of cyclohexene with molecular oxygen was studied in a batch reactor. The products, cyclohexene hydroperoxide, cyclohexenol, cyclohexenone and cyclohexene oxide were realised in the temperature range of 343}393 K. The e!ect of various kinetic parameters such as temperature, speed of agitation and wall material was studied. The kinetic data were generated at di!erent temperatures and "tted successfully with a rate equation based on autocatalysis by total products. The values of rate constants and activation energy were determined. Recognising the fact that the industrial route to cyclohexene from benzene hydrogenation yields a mixture of cyclohexene and cyclohexane which are di$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;
References: Baumgartner, H.J. (1983). Oxidation of isobutane in the dense phase and at low-oxygen concentration, US Patten 4,408,082. Criegee, R., Pilz, H., & Flygare, H. (1939). Ber. dtsch. Chem. Ges., 72, 1799 [cf. Kamneva and Pan"lova (1965)]. Fukuoka, Y., & Nagahara, H. (1991). A new cyclohexanol process via cyclohexene from benzene, Preprints of symposium on alkylation, aromatization, Oligomerization and isomerization of short chain hydrocarbons over heterogeneous catalysts. Division of Petroleum Chemistry, Inc., American Chemical Society 36 (4), 821}824. Ishada, H., & Ono, M. (1993). Preparation of high purity 1,3-cyclohexadiene from cyclohexene, Jpn. Kokai Tokkyo Koho JP 07,165,622 [cf. CA 123(1995):169282]. Ishada, H., & Ono, M. (1995). Preparation of 2-cyclohexene-1-ol by hydrogenolysis of cyclohexene hydroperoxide in the absence of hydrophilic solvents, Jpn. Kokai Tokkyo Koho JP 09,87,219 [cf. CA 127(1997):17442]. Kamneva, A.I., & Pan"lova, Ye.S. (1965). On the mechanism of autoxidation of cyclohexene. In N.M. Emanuel (Ed.), ¹he oxidation of hydrocarbon in the liquid phase (p. 219). UK: Pergamon Press. Neuburg, H.J., Phillips, M.J., & Graydon, W.F. (1976). Kinetic study of the liquid phase oxidation of cyclohexene catalysed by manganese oxide. Journal of Catalysis, 38, 33}46. Shah, U. (1998). Oxidation of isobutane in liquid phase and under supercritical conditions. M.Sc. thesis, Monash University, Australia. Suresh, A.K., Sridhar, T., & Potter, O.E. (1988a). Mass transfer and solublity in autocatalytic oxidation of cyclohexane. ¹he American Institute of Chemical Engineers Journal, 34, 55. Suresh, A.K., Sridhar, T., & Potter, O.E. (1988b). Autocatalytic oxidation of cyclohexane-modelling reaction kinetics. ¹he American Institute of Chemical Engineers Journal, 34, 69. Suresh, A.K., Sridhar, T., & Potter, O.E. (1988c). Autocatalytic oxidation of cylohexane-mass transfer and chemical reaction. ¹he American Institute of Chemical Engineers Journal, 34, 81. Suresh, A.K., Sridhar, T., & Potter, O.E. (1990). Catalysed oxidation of cylohexane in the liquid phase. ¹he American Institute of Chemical Engineers Journal, 36, 137. Takehara, K., Hayakawa, T., & Ishikawa T. (1980). Heterogeneous catalysis in the liquid phase oxidation of ole"n, V-oxidation of cyclohexene with supported molybdenum-chromium binary oxide catalyst. Journal of Catalysis, 66, 267}280. Vaiser, V.L. (1949). Doklady Akademic Nauk SSSR, 67, 839 [cf. Kamneva and Pan"lova (1965)]. Van Sickle, D.E., Mayo, F.R., & Arluck, R.M. (1965). Liquid-phase oxidation of cyclic alkenes. Journal of American Chemical Society, 87 : 21 (5), 4824}4832. Wen, Y., Potter, O.E., & Sridhar, T. (1997). Uncatalysed oxidation of cyclohexane in a continuous reactor. Chemical Engineering Science, 52 (24), 4593}4608. Acknowledgements The authors acknowledge "nancial support from the Australian Research Council. Notation C k r t ¹ x Subscripts cy Superscript 0 initial cyclohexene concentration, kmol/m rate constant, m / kmol h rate of the reaction, kmol/m h time h temperature, K total conversion