纤维素转化制有机酸是生物质高值化利用的重要途径，然而纤维素的难溶性限制了高效转化。针对固体酸催化纤维素转化受限于固－固相传质的问题，本项目创新性地提出构造基于掺N碳材料（C-NHx）的温控响应酸碱双环境多功能催化体系，催化纤维素高效转化制有机酸的新思路。通过设计制备介孔C-NHx材料，调控N原子碱性和材料结构性质，研究不同N碱位和不同HX之间温控释放“摆动效应”以及催化纤维素水解转化过程，阐明温控释放质子强酸（HX）作用机制以及碱性中心和酸性中心的相互转化和失活机制，构建高效催化纤维素定向转化的催化体系；将快速微反应技术和量子化学计算相结合，研究纤维素水解、异构化、逆向羟醛缩合和分子内羟基重排反应的催化反应过程，揭示酸碱活性中心与各反应间的催化机理；研究酸碱双环境下纤维素定向转化制有机酸过程，阐明复杂反应体系中各反应间的耦合作用机制，为实现纤维素定向转化制小分子羧酸奠定理论基础。

Targeted transformation of cellulose to small organic acids is a promising pathway for biomass utilization. However, insolubility of cellulose in solvents severely impedes its hydrolysis and transformation to value-added chemicals. Aiming to break through the mass transfer obstacle between solid catalyst and cellulose particles during cellulose hydrolysis, herein we propose a creative approach to construct a biphase catalytic system (an acidic aqueous phase and a basic solid phase) based on N-doped carbon materials (C-NHx) by this way cellulose hydrolysis and further transformation to carboxylic acids can be enhanced. More clearly, this approach is realized by taking advantage of the versatile basic site of N atoms in mesoporous N-doped carbon materials, the adsorbed proton acids (HX) is released at high temperature into aqueous phase and thus form an acidic environment that is able to accelerate the hydrolysis reaction. On the same time, the residual C-NHx after releasing HX is a basic solid that can catalyze the isomerization of glucose to fructose, retro aldo condensation as well as the further reaction to form carboxylic acids. Our research objectives are: (1) to elucidate the temperature dependence of HX on the species of the N atom basic sites as well as the mutual transformation mechanism of acidic sites and basic sites by means of designing and preparing various mesoporous N-doped carbon materials and construct catalytic system suitable for highly effective transformation of cellulose; (2) to unveil the catalytic mechanism of active sites for catalyzing various reactions, including cellulose hydrolysis to glucose, glucose isomerization to fructose, retro aldol condensation and rearrangement reaction to form carboxylic acids by combining fast micro-reaction technique with quantum chemistry analysis; and (3) to get insight into the coupling mechanism of these reaction during one-pot conversion of cellulose to acetic and lactic acids. The study of this project will lay the theoretical foundation for targeted transformation of cellulose to small carboxylic acids.