the non-phenolic lignin model compounds and radicals produced from azocompounds in air have previously been analysed, and peroxyl radical (PR) is postulated to be responsible for lignin degradation (Kapich et al., FEBS Lett., 1999, 461, 115–119). However, because the thermolysis of azocompounds in air generates both a carbon-centred radical (CR) and a peroxyl radical (PR), we re-examined the reactivity