Analytical pyrolysis products derived from cinnamyl alcohol-end groups in lignins

The contributions of cinnamyl alcohol-end groups to lignin-derived pyrolysis products were studied using coniferyl alcohol benzyl ether I, a model compound for cinnamyl alcohol-end groups. The profile of the pyrolysis product distribution of I demonstrated that cinnamyl alcohol-end groups are greatly responsible for the formation of propenylphenols, and cinnamyl compounds (dihydrocinnamyl alcohols, cinnamaldehydes, and cinnamyl alcohols), but play a small role in the formation of the products with a short side-chain (< C3). The contributions of coniferyl alcohol-end groups were examined in pyrolyses of reference lignins, a bulk dehydrogenative polymer of coniferyl alcohol (DHP), a Japanese cedar (Cryptomeria japonica D. Don) wood and its milled wood lignin. Large similarity of the distribution profile of the cinnamyl compounds in the DHP pyrolyzate to that in the I pyrolyzate showed that coniferyl alcohol-end groups play st large role in the DHP pyrolyzate. The distribution profiles of the cinnamyl compounds in the cedar wood and its lignin pyrolyzates were greatly differed from that of the I pyrolyzate. (C) 2000 Elsevier Science B.V. All rights reserved.