Oxidation of terpenes in H-mordenite

Abstract

The behaviour of three terpenes, α-pinene, trans-isolimonene, and α-terpinene, in H-mordenite was investigated by EPR. All three species were found to give the same EPR spectrum, which was assigned to the radical cation of α-terpinene. No deuterium was incorporated when α-pinene in D-mordenite was measured, suggesting that rearrangement to α-terpinene is not catalysed by Brønsted acidity but probably by Lewis sites.