Guo Tian-Shui, Xu Ying-Hong, Li Ming-Fei, Ma Jian-Feng
Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing 100083, China.
Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing 100083, China; State Key Laboratory of Bio-Fibers and Eco-Textiles, Qingdao University, Qingdao, Shandong 266071, China.
Int J Biol Macromol. 2022 Apr 15;204:364-372. doi: 10.1016/j.ijbiomac.2022.02.016. Epub 2022 Feb 8.
Formic acid is an attractive solvent for the fractionation of lignocellulose for the production of biomaterials and chemicals, while the operation conducted in a batch manner is not conducive to mass transfer in separation process. In this research, eucalyptus was fractionated with formic acid/hydrochloric solution in a flow-through reactor at 95 °C, and the structural characteristics and the composition of fractionated lignin in different stages were investigated. Results showed that the fractionation efficiency was notably improved with a flow-through reactor, as evidenced by the low solid residue yield of 49.5% and the lignin removal rate of 79.4% as compared to the batch manner. During the fractionation process, the dissolution rate of lignin decreased gradually, and the obtained lignin samples showed low molecular weight (<3000), good uniformity (<2), and high thermal stability. The structure analysis showed that β-O-4, β-β, and β-5 linkages in lignin were degraded to varying degrees with increased time, and the degradation of G units was more severe than S ones.
甲酸是用于木质纤维素分级分离以生产生物材料和化学品的一种有吸引力的溶剂，然而以间歇方式进行的操作不利于分离过程中的传质。在本研究中，桉木在95℃下于流通式反应器中用甲酸/盐酸溶液进行分级分离，并研究了不同阶段分级木质素的结构特征和组成。结果表明，使用流通式反应器时分级效率显著提高，与间歇方式相比，固体残渣产率低至49.5%，木质素去除率达79.4%。在分级过程中，木质素的溶解速率逐渐降低，所获得的木质素样品显示出低分子量（<3000）、良好的均匀性（<2）和高热稳定性。结构分析表明，随着时间增加，木质素中的β-O-4、β-β和β-5键发生不同程度的降解，且G单元的降解比S单元更严重。
