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Assessment of the competitiveness of the radical and nonradical mechanisms in the acid-catalyzed oxidation of styrene epoxide

Research paper by L. V. Petrov, B. L. Psikha, V. M. Solyanikov

Indexed on: 24 May '09Published on: 24 May '09Published in: Petroleum Chemistry



Abstract

The oxidizability value of styrene epoxide as the ratio k2/√k6, where k2 and k6 are the propagation and termination rate constants of the epoxide oxidation chain, respectively, was calculated from experimental data on the oxidation of neat styrene epoxide with oxygen in the presence of the initiator dicumyl peroxide in a quartz reactor of a manometric unit. Alternative calculations of the oxidizability value with the use of two procedures and two experimental setups yielded close values of k2/√k6 = 0.333exp(−22.5 kJ mol−1/RT) and k2/√k6 = 0.18exp(−22.1 kJ mol−1/RT)(l/(mol s))1/2 (393–413 K), which characterize a quite high stability of styrene epoxide toward oxidation by peroxide radicals. With allowance for the new data, it was concluded that the radical mechanism is unfeasible under the conditions of the earlier-studied mild acid-catalyzed oxidation of styrene epoxide (333–348 K).