SELECTIVE CERIUM-CATALYZED OXIDATION OF ALKYL BENZENES TO BENZYL-ESTERS BY BROMATE SALTS

Benzyl esters are formed catalytically at moderate temperatures from a lkyl benzenes by KBrO3 in the presence of cerium ammonium nitrate (CAN ). Toluene gives in acetic acid benzyl acetate. Ethylbenzene, cumene, 4-tert-butyltoluene and 4-bromotoluene give similar oxidation products . p-xylene undergoes a selective mono-acetoxylation reaction in acetic acid. The bromate salt is acting as an oxidant for the alkylbenzene a nd a cooxidant for the Ce salt. The Ce salts (Ce(III), Ce(IV)) serve b oth as oxidation catalysts and as Lewis acids that catalyze the conver sion of benzyl bromide in the reaction mixture to benzyl ester.