Delignification Mechanism During High-Boiling Solvent Pulping. V. Reaction of Nonphenolic β-O-4 Model Compounds in the Presence and Absence of Glucose

Abstract

Nonphenolic β-aryl ether model compounds, veratrylglycerol-β-guaiacyl ether (1) and its α-ethyl ether (2) were treated in 70% aqueous 1,4-butanediol solutions at 180°C. The reactivity of compound 2 was higher than that of compound 1. Benzyl ether formation with 1,4-butanediol was observed. This suggests the high reactivity of lignin–carbohydrate complex with benzyl ether type under HBS pulping conditions. On the other hand, guaiacol was not detected in the reaction mixture. This indicates that β-aryl ether in nonphenolic structures is inert to HBS pulping conditions. Addition of glucose and acetic acid enhanced the benzyl ether formation with 1,4-butanediol, but not cleavage of β-aryl ethers.