Addition of 1,4-dihydroxybenzene (hydroquinone) to the styrene epoxide-para-toluenesulfonic acid binary system subjected to oxidation in a solution of 90 vol % tert-butanol with 10 vol % chlorobenzene increases the styrene epoxide consumption rate and the rate of oxygen uptake by the system and leads to buildup of benzaldehyde. The ratio of the O-2 uptake rate to the overall rate of styrene epoxide consumption in the hydroquinone-styrene epoxide-para-toluenesulfonic acid ternary system is (V (O2)/V (SE)) ae 0.24 (343K), which is 3.5 times that for the epoxide-acid binary system.