Liquid-phase oxidation of hydrocarbons. Part 4.—Indene and tetralin: occurrence and mechanism of the thermal initiation reaction with oxygen

A study has been made of the possibility of a liquid-phase molecular reaction between oxygen and the hydrocarbons indene and tetralin by fully inhibiting the autoxidation chain. The hydroperoxide-inhibitor reaction AH+ROOH→A˙+RO˙+H2O is believed responsible for the autoacceleration observed. The occurrence of an oxygen+hydrocarbon reaction by a third-order reaction has been reasonably established. This order is consistent with a termolecular process, [graphic omitted] where ki= 2.4 × 105 exp (–23800±1500//RT)mole–2 l.2 sec–1, (tetralin)ki= 3.9 × 103 exp (–18800±1500//RT)mole–2 l.2 sec–1. (indene) The mechanisms of the initiation processes are discussed, and the possible role of charge transfer complexes is considered.