Jiangsu Provincial Key Laboratory of Pulp and Papermaking Science and Technology, Nanjing Forestry University, Nanjing 210037, China.
Molecules. 2023 Jun 8;28(12):4637. doi: 10.3390/molecules28124637.
Lignin structure is an important factor affecting the cooking part of the pulping process. In this study, the effect of lignin side chain spatial configuration on cooking performance was analyzed, and the structural characteristics of eucalyptus and acacia during cooking were compared and studied by combining ozonation, GC-MS, NBO, and 2D NMR (H-C HSQC). In addition, the changes in the lignin content of four different raw materials during the cooking process were studied via ball milling and UV spectrum analysis. The results showed that the content of lignin in the raw material decreased continuously during the cooking process. Only in the late cooking stage, when the lignin removal reached its limit, did the lignin content tend to be stable due to the polycondensation reaction of lignin. At the same time, the E/T ratio and S/G ratio of the reaction residual lignin also followed a similar rule. At the beginning of cooking, the values of E/T and S/G decreased rapidly and then gradually rose when they reached a low point. The different initial E/T and S/G values of different raw materials lead to the disunity of cooking efficiency and the different transformation rules of different raw materials in the cooking process. Therefore, the pulping efficiency of different raw materials can be improved using different technological means.
木质素结构是影响制浆蒸煮过程的一个重要因素。本研究分析了木质素侧链空间构型对蒸煮性能的影响，通过结合臭氧化、GC-MS、NBO 和二维 NMR（H-C HSQC），对比研究了桉树和相思木在蒸煮过程中的结构特征。此外，通过球磨和紫外光谱分析研究了四种不同原料在蒸煮过程中木质素含量的变化。结果表明，原料中的木质素含量在蒸煮过程中持续下降。只有在后期的蒸煮阶段，当木质素的去除达到极限时，由于木质素的缩聚反应，木质素含量才趋于稳定。同时，反应残余木质素的 E/T 比和 S/G 比也遵循类似的规律。在蒸煮开始时，E/T 和 S/G 值迅速下降，然后在达到最低点时逐渐上升。不同原料的初始 E/T 和 S/G 值不同，导致蒸煮效率不一致，不同原料在蒸煮过程中的转化规律也不同。因此，可以使用不同的技术手段来提高不同原料的制浆效率。
