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以碱木质素为原料,采用磺甲基化反应,得到磺甲基化木质素(SAL),并进一步采用辣根过氧化物酶(HRP)催化以提高其分子量,制备了高分子量高磺化度磺甲基化木质素(HPSAL).采用凝胶渗透色谱、红外光谱、核磁共振氢谱、紫外光谱和顶空气相色谱等研究了改性前后SAL的结构特征.结果表明,经HRP催化后,与SAL相比,HPSAL的重均分子量和磺化度显著增加,分别提高20倍和30%以上,羧基含量升高,而甲氧基和酚羟基含量降低.HRP使SAL形成酚氧自由基,活化其酚羟基的邻、对和侧链Cβ位,增加磺化反应活性,而磺化度的提高又有利于增加HRP催化SAL的聚合反应活性,其聚合方式主要为β-O-4’、β-β’、β-1’和β-5’联结.分子模拟结果表明,甲氧基含量的降低和磺酸基含量的增加能显著提高以β-O-4’连接键为主的聚合反应活性.
Using alkali lignin as raw material, sulfomethylation reaction was used to obtain sulfomethylated lignin (SAL), and HRP was further used to increase its molecular weight. High molecular weight sulfonated (HPSAL) .The structural characteristics of SAL before and after modification were investigated by gel permeation chromatography, infrared spectroscopy, 1H nuclear magnetic resonance spectroscopy, ultraviolet spectrum and headspace gas chromatography.The results showed that after the catalysis with HRP , Compared with SAL, the weight average molecular weight and sulfonation degree of HPSAL significantly increased by 20 times and 30% respectively, while the content of carboxyl group increased while the content of methoxy group and phenolic hydroxyl group decreased. , Activation of the phenolic hydroxyl group ortho, para and side chain Cβ position, increase the sulfonation activity, and the improvement of the degree of sulfonation is also conducive to increase HRP catalytic SAL polymerization activity, the polymerization mainly β-O-4 ’ , Β-β ’, β-1’ and β-5 ’.The molecular simulation results show that the decrease of methoxy content and the content of sulfonic acid groups can significantly increase the β-O-4’ linkage Polymerization activity.