Free radicals from biogenic volatile organic compounds (VOC's): an electron spin resonance investigation

Electron spin resonance has been used to characterise free radicals formed by the reactions of photochemically generated tert-butoxyl radicals with a-pinene, P-pinene, a-terpinene, y-terpinene, car-2-ene, car-3- ene and limonene. The spectra have been interpreted using computer analysis and simulation and assigned to substituted cyclohexenyl or cyclohexadienyl radicals formed by abstraction of a hydrogen atom from the parent terpene.