基于全溶体系的木质素分离与表征

Isolation and Characterization of Lignin-based on Complete Dissolution System

为获取完整的木质素化学结构,全面深刻解析木质素的结构特性,以球磨2 h的杨木为原料,通过LiCl/DMSO溶解体系溶解、再生处理,纤维素酶解,再经分离、纯化得到杨木溶解再生酶解木质素(DEL),得率和纯度分别为42.1%、39 g/kg,均高于单纯纤维素酶解木质素(CEL)。DEL分子质量较低,分散性更均一,分离过程中低分子质量的木质素更易溶出。通过碱性硝基苯氧化反应,表征了DEL的缩合程度,进一步证明了DEL为GS型木质素,且分离过程中,木质素的未缩合结构单元比例、缩合程度未发生变化。

In order to obtain the complete chemical structure of lignin and comprehensively and profoundly analyze the structural characteristics of lignin,using poplar wood with ball milling for 2 h as raw material,the dissolving regenerative enzymolysis poplar lignin(DEL)was obtained by treatment of LiCl/DMSO system dissolution and regeneration,enzymatic hydrolysis,followed by extraction and purification.Compared with single cellulose enzymosis poplar lignin(CEL),the yield and purity of DEL were 42.1%and 39 g/kg,respectively,which were higher than those of CEL.The results showed that the molecular weight of DEL was lower and its dispersity was better,and the lignin with lower molecular weight dissolved more during the separation process.The condensation degree of DEL was characterized by an alkaline nitrobenzene oxidation reaction,which further demonstrated that DEL was GS-type lignin,and the proportion of uncondensed structural units with condensation degree of lignin did not change during the separation process.