Tetramethylammonium hydroxide thermochemolysis of guaiacyl-syringyl and guaiacyl dehydrogenation polymers

摘要

Tetramethylammonium hydroxide thermochemolysis of lignin was investigated using guaiacyl-syringyl and guaiacyl dehydrogenation polymers. The guaiacyl-syringyl mixed polymer provided: (1) 1-(3.4-dimethoxyphenyl)- 1,2,3-trimethoxypropane isomers (11/12) and 1-(3,4,5-trimethoxyphenyl)-1,2,3-trimethoxypropane isomers (15/16) as beta-aryl ether subunit-derived products, (2) 2,3,3',4'-tetramethoxy-5-(3-methoxyprop-1-enyl)stilbene (18) and 2,3,3',4',5'-pentamethoxy-5-(3 -methoxyprop-1-enyl)stilbene (22) as beta-5 subunit-derived products, (3) pinoresinol dimethyl ether (21), medioresinol dimethyl ether (23) and syringaresinol dimethyl ether (24) as beta-beta subunit-derived products, respectively: and (4) coniferyl alcohol dimethyl ether (8) and sinapyl alcohol dimethyl ether (14) from 4-O-linked coniferyl and sinapyl alcohols. The ratio of products stemming from beta-aryl ether, beta-5 beta-beta subunits was 23:13:64. The guaiacyl polymer provided 11/12, 18, 21, and 8, suggesting the same reactions occurring also in the guaiacyl polymer, although the ratio (31:32:37) of the products from beta-aryl ether, beta-5, beta-0 subunits differed. (C) 2004 Elsevier Ltd. All rights reserved.