Study on the Mechanism of Auto-catalyzed Ethanol-water Pulping of Aspen
This paper studied the reaction course and kinetics of delignification in the process of auto-catalyzed ethanol-water pulping.The results showed that delignification of aspen by auto-catalyzed ethanol-water pulping followed the law of first progression reaction.The delignification reaction could be separated into two phases.The structural changes of aspen lignin during auto-catalyzed ethanol-water pulping were also studied by 1H-NMR.It was showed that the linkages of alkylaryl ether of iignin,such as the α-ether linkages(α-O-4)and the β-ether linkages(β-O-4),were broken and the part of aryl formed carbenium at the Cα and Cβ of acyclic branch.Meanwhile,the aryl part of ether accepted one H+ and formed phenol.Because the electronegative effect originated from the electron cloud of phenyi,partial carbenium of Cβ was reset.Due to its ether or hydroxyl linkage resetting to Cβ,the Cα was changed into carbenium and formed new β-O-4 alkylaryl ether.The β-O-4 alkylaryl ether did not possess stability,so it was broke again.The large molecule of lignin was disintegrated into smaller one and dissolved into ethanol.Finally,α+ carbenium reformed α-O-4linkages of ether with phenol.
aspen auto-catalyzed ethanol-water pulping reaction course kinetics lignin structure
SUI XIN-JIN ZHOU JING-HUI
Dalian Polytechnic University,Dalian,116034,China;Liaoning Province Key Laboratory of Pulp and Paper Engineering,Dalian,116034,China
国际会议
第二届国际造纸与环境学术会议(The Second International Papermaking & Environment Conference)
天津
英文
327-330
2008-05-14（万方平台首次上网日期，不代表论文的发表时间）