Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Beijing Key Laboratory of CO2 Utilization and Reduction Technology, Department of Energy and Power Engineering, Tsinghua University

本工作研究了水热过程中解耦的温度和压力对木质素的影响，评估了水热处理对于木质素结构的影响，评估了解耦温度和压力对于木质素水热过程液相产物的影响。结果表明，木质素全部由松柏醇的G型单体组成，水热处理后，木质素中的β–O–4酯键等C–O键发生断裂，甲氧基以及和含氧结构相连的脂肪族结构转化为脂肪族碳骨架。液相产物最初为香草醛和3-(4-羟基-3-甲氧基苯基)-1-丙醇，后续主要通过单体间的转化以及木质素末端愈创木基单元的β–O–4键的裂解为愈创木酚。解耦的高压会抑制木质素液相产物的产生，并且会降低产物中异丁香酚的选择性。本研究结果有望为木质素的水热转化过程工况的优化提供更为基础的认识和理解。

This study investigated the effects of decoupled temperature and pressure on lignin during the hydrothermal process. The effect of hydrothermal treatment on the lignin structure was evaluated, and the effects of decoupling temperature and pressure on the liquid products of the lignin were assessed under decoupling conditions. The results showed that lignin was composed almost entirely of the G-type monomer of coniferyl alcohol. After hydrothermal treatment, C–O bonds such as β–O–4 ester bonds in lignin were broken. Methoxy and aliphatic structures linked to oxygen-containing structures were converted into aliphatic carbon skeletons. The liquid phase products were initially vanillin and 3-(4-hydroxy-3-methoxyphenyl)-1-propanol, which were subsequently converted to guaiacol mainly by inter-monomer conversion and cleavage of the β–O–4 bond of the terminal guaiacyl unit of lignin. The decoupled high pressure inhibited the production of lignin liquid products and decreased the selectivity of isoeugenol in the products. The results of this paper are expected to provide more fundamental knowledge and understanding for the optimization of hydrothermal conversion process conditions of lignin.

北京市自然科学基金（2222012），广东省重点研发计划（2020B1111380001），国家自然科学基金（52070116）和清华大学山西清洁能源研究院种子基金资助

于士杰, 赵鹏, 刘茂清, 高宇, 李清海, 张衍国, 周会. 温度-压力解耦对木质素水热过程中结构变化及解聚产物的影响[J]. 燃料化学学报（中英文）, 2023, 51(8): 1106-1113.

YU Shi-jie, ZHAO Peng, LIU Mao-qing, GAO Yu, LI Qing-hai, ZHANG Yan-guo, ZHOU Hui. Effects of decoupled temperature and pressure on the hydrothermal process of lignin[J]. Journal of Fuel Chemistry and Technology, 2023, 51(8): 1106-1113.