Tetramethylammonium Hydroxide(TMAH)Thermochemolysis of Lignin:Behavior of 4-OMICRON-Etherified Cinnamyl Alcohols and Aldehydes

摘要

The thermochemolytic behavior of 4-OMICRON-etherified cinnamyl alcohols and aldehydes in lignin was investigated in the presence of tetramethylammonium hydroxide(TMAH)(315 deg C/4 s),using veratrylglycol-beta-(coniferyl alcohol)ether(1a),veratrylglycol-beta-(sinapyl alcohol)ether(1b),and veratrylglycol-beta-(coniferyl aldehyde)ether(2).The methylated products were monitored with gas chromatography-mass spectrometry.Dimers 1a and 1b provided the coniferyl and sinapyl alcohol dimethyl ethers consisting of three isomers,respectively.Coniferyl alcohol dimethyl ether isomers were also observed in the TMAH thermochemolysis pyrolysates of a bulk dehydrogenation polymer of coniferyl alcohol and a Japanese cedar(Cryptomeria japonica)wood.Coniferyl aldehyde methyl ether was not provided from TMAH thermochemolyses of coniferyl aldehyde,2,a dehydrogenation polymer of coniferyl aldehyde,and the cedar wood.The former three provided veratryl aldehyde in a large abundance,instead of coniferyl aldehyde methyl ether.Sinapyl aldehyde provided 3,4,5-trimethoxybenzaldehyde in a large abundance and sinapyl aldehyde methyl ether in a trace abundance.The results showed that TMAH thermochemolysis is an effective tool to obtain information on cinnamyl alcohol end groups,but is not applicable to analysis of cinnamyl aldehyde end groups.