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

Abstract

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 a 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.