镍钯配合物催化内烯烃的链行走聚合研究

Polymerization of alkene plays pivotal roles in polymer chemistry. Nickel and palladium complexes ligated by imine have attracted considerable attentions as a catalyst for alkene polymerization in recent years. The unique behavior of the nickel or palladium catalysts is attributed to the ability of the propagating metal-alkyl species to migrate along the growing polymer chain via rapid β-hydride elimination and reinsertion (chain-walking). Polymerization of internal alkenes which have two substituents at both ends of the double bond have been reported only in a limited number of cases, were investigated to synthesize novel polymers which can be obtained only by chain-walking polymerization at present. Therefore, this topic will focus on the chain-walk polymerization of internal alkene through three aspects: (1) Design and synthesize of new nickel and palladium catalysts ligated by imine ligands structures, and select the catalyst that the catalysis activation is the best; (2) The chain-walking polymerization of different types (linear, branched, substituted etc.) of internal alkenes with nickel and palladium catalysts were investigated in detail to synthesize novel polymers, and the polymerization mechanism was deduced with microstructure analysis of polymer; (3) Copolymerization of ethylene and polar group-substituted internal alkenes such as oleic acid and oleic acid esters were also investigated by palladium catalysts to synthesize polyethylene-based functional materials.

烯烃聚合反应在聚合物化学中有着举足轻重的作用。近年来，由含亚胺配体的镍钯配合物催化烯烃聚合反应引起了人们的高度关注。这类金属催化剂具有独特的链行走聚合行为，即金属烷基物可在聚合物主链上移动，通过快速β-氢消除和重新插入而完成催化聚合。聚合物化学中关于内烯烃（双键两端含有取代基的烯烃）聚合的报道非常有限，目前内烯烃只能通过链行走聚合的方式合成新型聚合物。因此，本课题将围绕内烯烃的链行走聚合反应开展三方面工作：（1）设计和合成新型亚胺镍钯催化剂，通过调控配体，筛选出催化活性最佳的催化剂；（2）应用筛选的催化剂实现以前没有解决的内烯烃聚合问题，并催化直链，支链，官能团取代等不同类型的内烯烃聚合，制备新结构类型的聚合物，分析聚合物的微观结构并研究其聚合机理；（3）钯催化体系应用于乙烯与含极性官能团内烯烃（如油酸，油酸酯类）的共聚反应，合成基于聚乙烯改性的功能化材料。

通过后过渡金属催化烯烃聚合反应制备新型聚烯烃材料具有重要意义和挑战性。本项目已经设计和制备了多个系列的新型镍和钯催化体系，主要包含N,N-, N,O-, N,P-和P,O-型配体结构。并且探究了这些催化剂体系在乙烯，1-烯烃和内烯烃的催化聚合能力，制备出新型结构的聚烯烃产品。根据所得聚合物微观结构的分析，首次提出了内烯烃链行走的通用聚合机理，为筛选烯烃聚合催化剂提供了依据。聚合结果揭示聚合活性，所得聚合物的分子量和支化度结构不仅依赖有单体类型，而且也依赖于聚合温度和催化剂的空间结构。更为重要的是，通过优化金属配合物结构提高了链引发的效率，开发出了一类高性能烯烃聚合催化剂。这类催化剂明显了改善了乙烯聚合的催化性能，实现了乙烯与极性单体的共聚反应，制备了基于聚乙烯改性的功能化材料。. 在本项目的资助项目下，在相关领域以已在Inorg. Chem.，Polym. Chem., Organom etallics, Polymer, Appl. Organomet. Chem.等SCI国际学术期刊发表论文16篇, 发表中国发明专利3项(授权1项)。作为主持人承担了埃克森美孚和中化国际产学研校企合作研发项目3项（共计440万）。2020年作为负责人在安徽大学成功建立了一个产学研合作平台：《安大-埃克森美孚石油催化剂联合研发中心》。 研究团队已初步形成从原材料合成到产业化应用的“产学研”相结合发展模式。