Fine chemicals from singlet-oxygen-mediated degradation of lignin - a GC/MS study at different irradiation times on a steam-exploded lignin

One-hour irradiation of steam exploded lignin in the presence of singlet ox ygen gave products showing high molecular weights. The irradiation at diffe rent times gave sinapyl alcohol, 4-hydroxy-3,5-dimethoxybenzaldehyde, and 2 ,4-dioctylphenol. It is interesting to note the isolation of a dehydroabiet ic acid derivative only after the treatment of lignin with singlet oxygen f or 5 h. After 12 h irradiation of the same sample the presence of long chai n hydrocarbons (octadecane), alkenes (1-octadecene) or alcohols (1-eicosano l) was detected. (C) 2000 Elsevier Science S.A. All rights reserved.