磁性仿酶固体酸水相中催化纤维素水解机理研究

Based on the catalysis mechanisms of cellulose hydrolysis by both acid and enzyme, the program proposed that the magnetic mimetic enzyme solid acid catalyst for cellulose hydrolysis is prepared by introducing functional groups into the medified surface and internal hole channel using biomass as carbon-based materials. The selection mechanism and evaluation method are established by investigation the effects of surface characterization and channel structure of carbon based material on the functional groups loading. The regulation mechanism of particle size and mosaic method in the internal channel is obtained by study on the distribution of magnetic Fe3O4 particle in solution and catalyst channel. The effect of each factor on the stability of functional groups and Fe3O4 particle in hydrothermal enviroment, and reaction mechanism between functional groups and glycoside bonds of cellulose are obtained by investigating the cellulose hydrolysis reaction. Based on the characterizations of high active and selective carbon based materials, and mass transfer principle during the reaction, macro kinetic model, which can provide a guidance for catalyst preparation and hydrolysis conditions optimum, is developed. After finish the program, a new energy conservation and environmental protection way for the utilization of cellulose energy is provided.

结合酸和酶催化纤维素水解的反应机理，本项目提出以生物质为碳基材料，分别将功能化官能团和磁性Fe3O4颗粒引入至修饰改造过的材料表面和孔道中，制备水相中催化纤维素水解的磁性仿酶固体酸催化剂。通过考察碳基材料种类及其表面性质和孔道结构对官能团负载量的影响，建立碳基材料的选择机制和评价方法；通过考察磁性Fe3O4颗粒在溶液和催化剂孔道中的分布情况，总结磁性Fe3O4颗粒粒径的调控机制并建立在孔道中的镶嵌方法；通过对催化纤维素水解反应进行考察，明晰各因素对催化剂中官能团和磁性颗粒在水热环境中稳定性的影响机制以及官能团与纤维素糖苷键间的作用机理，阐述对纤维素水解具有高催化活性、选择性的碳基材料特性，明晰催化水解反应过程中的传质特性，建立宏观动力学模型，为催化剂制备和水解工艺优化提供理论指导。该项目的研究，可为节能环保地利用纤维素能源提供一条新思路。

木质纤维素类生物质中的半纤维素和纤维素成分的解聚糖化是将其利用制备燃料乙醇、燃料丁醇等液体燃料和平台化合物的第一步。目前，最有效的水解方法是利用无机酸作为催化剂在水热环境中将木质纤维素类生物质中的半纤维素和纤维素成分降解为可发酵的木糖和葡萄糖。本项目自2014年开始以来，开展了磁性仿酶碳基固体酸催化剂的制备及其催化反应过程研究，所开发出的3种碳基固体酸催化剂具有较高的催化活性、选择性以及稳定性，水解过程中可直接得到木糖，木聚糖的含量非常低。在150℃的水相中反应2h可得到74%的木糖收率，水解后的酶水解残渣在40FPU/g加酶量的条件下反应48小时即可得到91%的酶解率，该反应结果高于现有报道。研究过程中，主要考察了催化剂制备条件中各反应条件对催化剂在水相中稳定性的影响并确定调控机制；优化磁性碳基固体酸催化剂催化生物质降解的工艺条件，并阐述催化剂所含基团与糖苷键之间的作用规律，解析了考察反应过程中酸质子在生物质颗粒中的分布规律。截止项目执行到期，开发了3种具有高催化活性、选择性和稳定性的磁性仿酶碳基固体酸催化剂，已发表标注的学术论文31篇，其中SCI收录17篇，另有1篇SCI论文在投；申请发明专利6项，圆满达到了计划书中的规定指标。