复合碱定向解聚绿竹碱木质素制备酚类化合物的研究

Preparation of Phenolic Compounds by Selective Depolymerization of Alkali Lignin from Sinocalamus Oldhami Using Composite Alkali

以绿竹碱木质素为原料,探究了不同碱催化剂降解木质素对酚类产物的影响。结果表明,复合碱催化剂在温和的水热体系中可实现对木质素的高效降解,其中,由Na OH和亲核试剂Na2SO3组成的复合碱降解效果最优,木质素降解率(83.1±1.2)%和酚类化合物的相对含量(86.85%)最高,酚羟基含量相对于空白组提高了约244%;傅里叶变换红外光谱仪(FT-IR)、凝胶渗透色谱仪(GPC)和全二维气相色谱-高分辨飞行时间质谱联用仪(GC-MS)的分析结果表明,在复合碱体系中,Na OH和Na_(2)SO_(3)的协同作用可有效断裂木质素结构中的C—O键,使木质素发生定向解聚,并生成一系列低分子质量(<1000)的小分子化合物;其中,酚类产物主要包括苯酚、2-甲氧基-苯酚和4-乙基-苯酚等。

The production of phenolic compounds during lignin depolymerization using different alkaline catalysts was investigated by choos-ing Sinocalamus oldhami alkali lignin as raw material.The experimental results showed that the composite alkali systems could effectively de-polymerize the lignin under a mild hydrothermal condition,in which the composite alkali system comprising sodium hydroxide and sodiumsulfite exhibited the highest efficiency of lignin degradation(83.1±1.2)% and the yield of phenolic compounds(86.85%).Compared withthe control group,the phenolic hydroxyl content increased by approximately 244%.The results of FT-IR,GPC and GC-MS indicated that thesynergistic effect of Na OH and Na2SO3 in the composite alkali system could effectively cleave the C—O bonds in lignin,resulting in the selec-tive depolymerization of ligin to produce a series of small molecule compounds with low molecular weight(<1000),among which the phenoliccompounds mainly included phenol,2-methoxy-phenol,and 4-ethyl-phenol,etc.