CATALYTIC-OXIDATION OF ALKYLBENZENES WITH MOLECULAR-OXYGEN UNDER NORMAL-PRESSURE AND TEMPERATURE BY N-HYDROXYPHTHALIMIDE COMBINED WITH CO(OAC)(2)

A practical catalytic method to convert alkylbenzenes into the corresp onding carboxylic acids under atmospheric dioxygen at ambient temperat ure using a combined catalytic system consisting of N-hydroxyphthalimi de (NHPI) and Co(OAc)(2) was developed. For instance, the oxidation of toluene was completed by NHPI combined with Co(OAc)(2) under an oxyge n atmosphere at room temperature to give benzoic acid in 81% yield. Un der these conditions, o- and p-xylenes were selectively converted into the corresponding monocarboxylic acids without the formation of the d icarboxylic acids. ESR measurements showed that Co(II) species assists in the formation of phthalimide-N-oxyl (PINO), which is a key species in this oxidation, from NHPI.