包覆型非贵金属双功能催化剂的创制及其催化生物基三乙酸内酯串联转化的研究

Efficient and target-specific conversion of triacetic acid lactone (TAL), a new renewable platform compound that has been identified as “a versatile intermediate linking chemical catalysis and biological catalysis”, into value-added compounds could help overcome the shortfalls of either a purely chemical or purely biological approach for producing high-value chemicals from biomass. The primary objective of the current proposal is to explore and develop new catalyst that can deliver selective catalytic conversion of TAL to gamma -caprolactone and investigate the relevant reaction mechanism and pathways. Focusing on the key processes including hydrogenation/dehydration/hydrogenation of TAL to δ-caprolactone and the subsequent ring-opening/ring-closing of δ-caprolactone to gamma-caprolactone, special efforts will be dedicated to three aspects: building a library of encapsulated non-noble metals bifunctional catalysts; investigating the effects of encapsulation (element, structure, acid/base, polarity, etc.) on catalytic activity, selectivity, stability; preparing new solid acid with anti-deactivation; understanding the mechanistic pathways involved in the relevant processes, exploiting the concepts of the catalyst designing, seeking and fabricating highly efficient catalytic system for value-added utilization of TAL, thus providing guidance for design of bifunctional solid catalyst under severe hydrothermal conditions and development of new technologies for upgrading of biomass.

三乙酸内酯（TAL）是一种新型的生物来源平台分子，被认为是“联系生物催化和化学催化的桥梁化合物”，研究其高效转化利用有助于克服单一化学法或生物法制备生物基高值化学品的缺点。本项目旨在研究和开发TAL催化转化制伽马-己内酯的高选择性、高稳定性的新型催化剂，并探究该过程机理和反应途径。针对所涉及的TAL加氢/脱水/加氢串联制δ-己内酯及其后续δ-己内酯开环/关环串联制伽马-己内酯等关键过程，（1）借鉴核壳结构的理念，制备基于包覆结构的非贵金属双功能催化剂体系，系统认识包覆外层的组成、结构、酸碱性、极性等因素与催化活性、选择性、稳定性的关系；（2）研制在液相反应中酸性稳定且抗失活的新型固体酸；（3）明确相关过程的选择转化作用机制，拓展催化剂设计理念，开发TAL增值利用的高效催化体系。本项目的顺利实施将为水热、苛刻条件下双功能固体催化剂的设计、制备及高效生物质催化转化新技术的发展提供科学支撑。

三乙酸内酯（TAL）是一种微生物发酵来源的优势分子，被认为是“联系生物催化和化学催化的桥梁化合物”。生物来源（木质纤维素转化或微生物发酵）的多官能团化合物的催化转化面临两大挑战：一是液相反应容易导致多相催化剂流失或结构破坏；二是原料中残留的发酵来源氨基酸杂质会毒化金属活性位。为解决此问题，本项目开发了TAL催化转化制伽马-己内酯的高选择性、高稳定性的新型催化剂。针对所涉及的TAL加氢/脱水/加氢串联制δ-己内酯及其后续δ-己内酯开环/关环串联制伽马-己内酯等关键过程，借鉴核壳结构的理念，制备了多孔碳层包覆的非贵金属催化剂体系，系统认识了包覆外层的组成、结构等因素与催化活性、选择性、稳定性的关系；制备了分子筛包覆金属的双功能催化剂，不但能高效催化TAL加氢/脱水/加氢串联制δ-己内酯，而且分子筛包覆能够保护金属不受氨基酸毒化，提高催化剂循环使用稳定性；此外还研制了在液相反应中酸性稳定且抗失活的新型介孔磷酸铌固体酸。所开发的抗流失、抗毒化的包覆结构催化剂设计理念，为生物来源的多官能团化合物的催化转化中高效稳定多相催化剂的设计制备提供有效借鉴。