常压下酸催化多元醇液化纤维素反应机理的研究  

Liquefaction Pathway of Corn Stalk Cellulose in the Presence of Polyhydric Alcohols Under Acid Catalysis

作　　者：张妍 高壮志[1] 乔文朴 杨宇杰 常紫阳 刘忠 ZHANG Yan;GAO Zhuang-zhi;QIAO Wen-pu;YANG Yu-jie;CHANG Zi-yang;LIU Zhong(Key Laboratory of Recycling and Eco-treatment of Waste Biomass of Zhejiang Province,Zhejiang University of Science and Technology,Hangzhou 310023,China;Tianjin Key Lab of Pulp&Paper,Tianjin University of Science&Technology,Tianjin 300457,China)

机构地区：[1]浙江科技大学浙江省废弃生物质循环利用与生态处理技术重点实验室,浙江杭州310023 [2]天津科技大学天津市制浆造纸重点实验室,天津300457

出　　处：《光谱学与光谱分析》2024年第9期2577-2581,共5页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(32101465);浙江省自然科学基金项目(LQ23C160001)资助。

摘　　要：开发农林废弃物高值化利用路径与“深入推进能源绿色低碳转型”国家重大战略需求高度契合。实验探索农业废弃物玉米秸秆中纤维素组分常压酸(H3PO4)催化多元醇[丙二醇(PG)与二甘醇(DEG)混合液]液化反应路径为研究目标,了解酸催化多元醇作用条件下的木质生物质液化反应机理。采用傅里叶红外光谱(FTIR)、凝胶渗透色谱(GPC)、核磁共振波谱(NMR)及热重分析(TGA)对不同反应时间下纤维素液化所得生物油的化学基团、分子量及其分布、分子结构、热解等进行了分析。FTIR检测表明,不同反应时间所得生物油具有相似FTIR特征;液化初期,纤维素降解生成了较多的烃类、醚类和含羰基化合物;液化后期,纤维素中的糖类降解产物、羟基或烯烃与PG/DEG反应生成了难溶于1,4-二氧六环的有机物。GPC分析表明,随着液化的进行,纤维素分子链发生断裂程度加剧,降解生成低分子量(LMW)物质越来越多,降解反应占主导地位;而当反应时间达到某一值时,其降解产物与PG/DEG发生聚合反应产生越来越多的大分子量物质,使生物油的分子量不再降低,即聚合反应占主导地位。^(1)H-和^(13)C-NMR表明,纤维素在液化作用下发生降解使得分子链断裂,仍保留了部分葡萄糖单元结构;随着液化反应的进行,这些结构单元再次发生转化产生LMW化合物;反应继续进行时,这些产物之间或与PG/DEG之间可进行聚合反应,形成结构趋于一致、性质逐渐稳定的新物质。TGA分析结果:生物油中含有70%~85%碳数小于25和5%~10%碳数高于25的化合物,最终残炭率随着反应时间的延长先降低再升高。实验通过研究纤维素在多元醇液化过程中的结构变化,揭示其液化的反应历程,为探索秸秆全组分的液化机理奠定理论基础。The development of high-value utilization paths for agricultural and forestry waste was highly consistent with the major strategic demand to“further promote green and low-carbon energy transformation”.In this paper,the objective was to investigate the pathway of propanediol(PG)and diethylene glycol(DEG)liquefaction catalyzed by phosphoric acid of cellulose from corn stalk at atmosphere pressure,aiming at understanding the mechanism of lignocellulosic biomass liquefaction reaction under the action of acid-catalyzed polyhydroxy alcohols.The chemical groups,molecular weight and distribution,molecular structure,and pyrolyzation of cellulosebiofuels were analyzed by Fourier transform infrared spectroscopy(FTIR),nuclear magnetic resonance spectra(NMR),gelpermeation chromatography(GPC),and thermo gravimetric analysis(TGA).FTIR showed that the biofuels had similar FTIR characteristics.At the early liquefaction stage,cellulose degradation produced more hydrocarbons,ethers,and carbonyl compounds.At the later stage of liquefaction,the carbohydrate degradation products,hydroxyl or olefin in cellulose,reacted with PG/DEG to generate organic matter insoluble in 1,4-dioxane.GPC explained that with the progress of the reaction,the breakage degree of the cellulose molecular chain would be aggravated,and more and more low molecular weight(LMW)substances were generated by degradation.However,when the reaction time reached a certain value,the degradation products reacted with PG/DEG to produce larger molecular weight substances,resulting in the molecular weight of biofuel no longer being reduced.Results from 1 H-and 13 C-NMR presented that cellulose was degraded under liquefaction,and the molecular chain was broken,but part of the glucose structure was still preserved.With the reaction,these structural units were transformed again to produce LMW compounds.When the reaction continues,polymerization reactions could occur between these products or with PG/DEG,forming new substances with consistent structures and gradually stable pr

关 键 词：纤维素 生物油 红外光谱 凝胶渗透色谱 核磁共振 热重分析 

分 类 号：S216[农业科学—农业机械化工程]