K. Kuroda, A. Nakagawa-izumi
Jun 1, 2006
Citations
1
Influential Citations
48
Citations
Journal
Organic Geochemistry
Abstract
Abstract This paper addresses the behavior of β-5 substructures in analytical pyrolysis of lignin. Five phenolic 2-arylcoumarans containing a β-5 linkage, dehydrodiconiferyl alcohol ( I ) and II – V , and diazomethane-methylated I ( Im ), were pyrolyzed at 500 °C for 4 s. The products were analyzed by gas chromatography and gas chromatography/mass spectrometry. The major products of I – IV and Im were 4-methylguaiacol ( 4 ) and 1,2-dimethoxy-4-methylbenzene ( 4m ), respectively, stemming from the A moiety of the 2-arylcoumarans. 2-Arylcoumarans I – IV having the ring B with a CH CHCH 2 OH or CH CHCHO side chain provided 4 in a larger yield than dehydrodiisoeugenol ( V ) having the ring B with a CH CHCH 3 side chain; the yields of 4 were ∼6.6, 5.7–4.6, and 0.9 mol% from I , II – IV and V , respectively. Characterization of the dimeric products of I showed the α-aryl ether opened-dimers with the hydrogenated Cα–Cβ bond being the precursors of 4 . Based on these results, guaiacyl and syringyl β-5 substructures were proposed as potential pyrolytic origins for 4 and 3,5-dimethoxy-4-methylphenol in analytical pyrolysis of soft- and hardwood lignins.