OXIDATION REACTION

PROBLEM TO BE SOLVED: To minimize the corrosion, etc., of a production apparatus and to simply carry out the oxidation reaction of a substance to be subjected to oxidation reaction, by making the substance to be subjected to oxidation reaction exist in a formation system to form a peroxy acid. SOLUTION: A substance (e.g. cyclohexanone) to be subjected to oxidation reaction is oxidized with a peroxy acid in a formation system, in which an ester compound (e.g. butyl acetate) is formulated with hydrogen peroxide in the presence of an acid catalyst (e.g. methanesulfonic acid) and the peroxy acid is formed, to give an oxidation product (e.g. -caprolactone). In this case, the ratio of the ester compound (number of mols)/hydrogen peroxide (number of mols) is 1,000-1.2 and the amount of the acid catalyst used is about 0.001-50 wt.% based on the ester compound. The oxidation reaction can be applied to the epoxidation reaction of alkenes, the quinone derivative formation oxidation reaction of benzenes, Baeyer-Villiger reaction of cyclic ketones, etc.