综纤维素液相分解体系中呋喃类产物的生成和演变机理研究

Two furan derivatives, 5-hydroxymethylfurfural (HMF) and furfural (FF), are the platform chemicals， which can be produced from biomass and can be used for the generation of bio-based liquid fuels. This project mainly focuses on the mechanism study of the directional formation and evolution of HMF/FF during the liquid-phase decomposition of holocellulose in a multi-medium reaction system. Based on the structural characterization of the extracted holocellulose, the corresponding model compounds with typical sugar units will be selected for the experimental research in a high-pressure liquid-phase reaction system with multi-mediums. The influences of reaction conditions, ratios of reaction mediums and catalysts on the directional decomposition of model compounds into HMF/FF will be investigated, and the subsequent liquid-phase reaction of HMF/FF will also be studied. Through the calculation of molecular dynamics and density functional theory, a reaction model of the formation and evolution of HMF/FF during liquid-phase decomposition will be established. Finally, the liquid-phase directional conversion of holocellulose extracted from different biomass will be carried out, to investigate the influence of holocellulose structure on the formation of HMF/FF. Additionally, combining with reaction model of liquid-phase decomposition and the influencing mechanism of reaction mediums and catalysts, the formation and evolution pathway of HMF/FF during the holocellulose liquid-phase decomposition will be obtained.

通过生物质制取5-羟甲基糠醛（HMF）和糠醛（FF）等呋喃类平台化合物对于生产生物质基液体燃料具有重要意义，本项目拟采用实验研究与理论计算相结合的方式对综纤维素多介质液相分解体系中HMF/FF的定向生成和演变机理进行研究。首先对提取的综纤维素进行结构表征，针对性选取相应的典型糖单元模化物，在多介质溶剂高压液相反应系统上开展实验研究，考察工况参数、反应介质配比和催化剂对模化物定向分解生成HMF/FF的影响规律，并进一步开展HMF/FF液相深度反应的研究。结合分子动力学与密度泛函理论计算，建立模化物液相分解过程中HMF/FF的生成及其演变机理模型。并开展不同生物质中提取的综纤维素液相分解的定向转化研究，探索综纤维素的结构特征对液相分解过程中HMF/FF生成的影响规律，并结合模化物液相分解机理模型及反应介质和催化剂的影响机制，构建综纤维素液相分解体系中HMF/FF的生成和演变机理途径。

在微损提取生物质综纤维素组分的基础上，确定了各组分的特征官能团分布及组成。根据各组分的结构表征结果，选取了含有综纤维素典型单元的多种代表性模化物，开展了不同反应工况下模化物液相分解生成HMF/FF的实验研究，借助高效液相色谱法（HPLC）对相应的产物分布进行了定量分析。系统研究了所提取的生物质组分在多种不同催化反应体系中的液相分解行为，得出了多介质反应体系中综纤维素的定向转化规律，并进一步探索了有机溶剂效应对综纤维素糖单元构型的调变作用，以及溶剂效应对综纤维素降解生成HMF/FF/LA的影响机制。在深入研究液相产物生成规律的基础上，对源自葡萄糖、木糖和纤维素液相分解所生成的固体副产物腐黑质（humin）进行了结构表征，揭示了其生成机理与其热解典型产物的生成机制。此外，基于分子动力学构建出综纤维素液相分解机理模型，并在多介质反应体系中对综纤维素催化转化制取HMF/FF进行了分子层面的反应转化机理研究，阐明了NaCl、Lewis酸、Brønsted酸等助剂和催化剂对综纤维素液相分解过程中产物分布的影响机理，构建出了多介质液相反应体系中HMF/FF的生成和演变机理途径。