基于碳水化合物转化制γ-戊内酯的双功能催化剂的构建及催化性能研究

Recently, the conversion of cellulose, the most attractive biomass, into high value-added platform chemicals has received sharply increasing interest in academia and industry. γ-Valerolactone is one of the important platform chemicals, which can be produced in a sequential tandem process by degradation of cellulose and subsequent hydrogenation of the degradation products. Most of the recent studies carried out by hydrogenating the degradation products of cellulose, such as glucose, fructose and levulinic acid using inorganic acids and hydrogenation catalysts. However, the multi step process is complex and uneconomical, and the use of inorganic acids could lead to the pollution of the environment. In the present proposal, we will synthesize nitrogen-doped ordered mesoporous carbon solid acid carriers via a self-assembly process of nitrogen-contained carbon sources, owing to the high acid density, large surface area, uniform and adjustable pore size, and high chemical and mechanical stability of the mesoporous carbon solid acids and the adjustable polarity and the coordinative ability with metal particles of the nitrogen-doped mesoporous carbons. Next, we will prepare the as-prepared carriers supported noble metal bifunctional catalysts and apply them to the one-pot selective conversion of carbohydrates such as cellulose, fructose and glucose to γ-valerolactone for the first time. Our studies will focus on the formation mechanism of the nitrogen-doped mesoporous carbon solid acids and the bifuctional catalysts,the structure-property relationship, the catalysis reaction and deactivation mechanism of the as-prepared bifunctional catalysts and the conversion mechanism of the carbohydrates. The implementation of the present project has great scientific significance and application value in the effective application of biomass resources and the development of the environmentally friendly chemical processes.

将自然界数量巨大且价廉易得的纤维素转化为高附加值的平台化合物是生物质资源综合利用领域的研究热点之一。生物质基γ-戊内酯即是一种重要的平台化合物，可由纤维素经降解、加氢得到。目前对γ-戊内酯的合成研究多是分步进行，且在酸催化步骤多用无机酸催化剂，存在工序繁琐、生产成本高、污染环境等问题。本项目拟利用介孔碳固体酸酸密度大、比表面积和孔容大、化学和机械稳定性好、传质阻力小和含氮介孔碳表面极性可调、能与金属粒子配位等特点，用软模板法制备含氮介孔碳固体酸，负载贵金属制备新型双功能催化剂，催化纤维素、果糖、葡萄糖等碳水化合物"一锅法"选择性转化制γ-戊内酯。研究含氮介孔碳固体酸及其负载双功能催化剂的形成机理，深入研究催化剂的构效关系、作用机理、失活机理和碳水化合物转化机理。本项目的实施对促进生物质综合利用技术及绿色化工过程的发展具有重要的科学意义和实用价值。

将自然界数量巨大且价廉易得的纤维素转化为高附加值的平台化合物是生物质资源综合利用领域的研究热点之一。生物质基γ -戊内酯即是一种重要的平台化合物，可由纤维素经降解、加氢得到。目前对γ-戊内酯的合成研究多是分步进行，且在酸催化步骤多用无机酸催化剂，存在工序繁琐、生产成本高、污染环境等问题。本项目企在创制掺氮介孔碳负载的双功能催化剂，采用 “一锅法”技术选择性催化转化碳水化合物制γ-戊内酯。项目首先制备出一系列加氢催化剂以及具有加氢和酸/碱功能的双功能催化剂，深入研究了催化剂的制备条件与其催化性能之间的关系规律。其次，采用多种方法制备出介孔碳和掺氮介孔碳，负载贵金属制备出双功能催化剂，用于碳水化合物催化加氢脱水制γ-戊内酯。结果表明，实验制备的催化剂对反应表现出良好的催化性能，掺氮介孔碳有助于金属在其表面分散和反应物的吸附，进而有助于提高催化剂的性能。在实验制备的掺氮介孔碳负载Ru催化剂上，乙酰丙酸转化率和γ-戊内酯收率均达到100%，并且催化剂具有很好的稳定性。深入研究了催化剂的形成机理、催化剂的构效关系、作用机理、失活机理和碳水化合物转化机理。此外，将催化剂制备技术和 “一锅法”反应技术进行了拓展，用于生物质催化转化制2,5-二甲基呋喃、伯胺等其他高附加值平台化合物，均取得良好的研究结果。本项目的研究结果对促进生物质综合利用技术及绿色化工过程的发展具有重要的科学意义和实用价值。