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从硫酸盐法桉木浆黑液中分离纯化得到硫酸盐木素,选取阿魏酸和丁香酸作为木质素模型物,探究谷氨酸在漆酶作为催化剂的条件下连接到木质素上的反应机理。结果表明:漆酶可以催化氧化木质素形成苯氧自由基或通过重排形成苯醌结构,自由基之间可通过耦合反应按摩尔比1∶1发生聚合;谷氨酸可与C5位置上的自由基发生Michael加成反应,使其自身连接到木质素上,在酸性条件下,对于苯环侧链末端醛基,C=O键可转变为C=N键将谷氨酸连接到木质素上,增加纸浆中的-COOH含量;
Kraft lignin was isolated and purified from kraftwood black liquor by sulfate method. Ferulic acid and syringic acid were selected as lignin models to explore the reaction of glutamic acid to lignin under the condition of laccase as catalyst mechanism. The results showed that laccase can catalyze the oxidation of lignin to form phenoxy radicals or form benzoquinone structure through rearrangement. The free radicals can be polymerized at a molar ratio of 1: 1 through a coupling reaction. Glutamic acid can react with C5 Free radical undergoes a Michael addition reaction to attach itself to the lignin. Under acidic conditions, the C = O bond can be converted to a C = N bond at the terminal aldehyde group on the benzene ring to attach glutamic acid to the lignin , Increase the -COOH content in the pulp;