The autoxidation of aliphatic esters. Part 1. The reactions of tert-butoxyl and cumyloxyl radicals with neopentyl esters

Six neopentyl esters have been selected, as models for pentaerythrityl este rs used as lubricants, to study the selectivity of hydrogen abstraction by alkoxyl radicals. Kinetic and product data for the reactions of two oxygena ted radicals, tert-butoxyl and cumyloxyl, with the six neopentyl esters bet ween 408 and 438 K have been determined. They show that attack by the radic als occurs at the alpha- and subsequent positions on the acyl moiety as wel l as at the alkyl group. The selectivity of the reactions is discussed in t erms of bond dissociation, steric and polar effects.