邻芳基卤素效应促进大位阻铁配合物催化不同分子量高度线性聚乙烯的合成  

o-Aryl Halogen Effect in Promoting The Synthesis of Linear Polyethylene with Varying Molecular Weights Catalyzed by Bulky Iron Complexes

作　　者：韩婷婷 吴新月 代胜瑜 HAN Tingting;WU Xinyue;DAI Shengyu(Institute of Physical Science and Information Technology,Anhui University,Hefei 230601,China)

机构地区：[1]安徽大学物质科学与信息技术研究院,安徽合肥230601

出　　处：《合成化学》2024年第12期1035-1041,共7页Chinese Journal of Synthetic Chemistry

基　　金：安徽省优秀青年基金资助项目(2108085Y06)。

摘　　要：配体的空间位阻和电子效应在后过渡金属催化的烯烃聚合中起着至关重要的作用。利用酸催化的2-R-6-二苯甲基-4-甲基苯胺(A1~A4)与2,6-二乙酰基吡啶缩合,合成了一系列带有大位阻二苯甲基取代基的邻芳基卤化吡啶二亚胺配体及其相应的铁催化剂(Fe1~Fe4)。利用FT-IR,质谱和元素分析对所得铁催化剂进行了全面的表征。这些铁催化剂具有较高的聚合活性(>10^(6) g·mol^(-1)·h^(-1)),能够产生较高的分子量(3.3~515.7 kg·mol^(-1))以及宽分子量分布(分散系数PDI=1.83~17.26)的高度线性聚乙烯。Fe4催化剂在30℃条件下能够生成分子量最高(515.7 kg·mol^(-1))的聚乙烯,并且在70℃时表现出最高的聚合活性(9.96×10^(6) g·mol^(-1)h^(-1))。此外,聚合温度对所得聚乙烯的分子量和分子量分布都有显著影响,较高的温度会导致形成分子量较低且分子量分布较窄的聚乙烯。邻芳基卤素对聚乙烯的分子量有重要影响,卤素取代基的原子半径大小决定了聚乙烯的分子量。The steric hindrance and electronic effects of ligands play a crucial role in the olefin polymerization catalyzed by late transition metals.In this study,a series of o-aryl halogenated bis(imino)pyridyl ligands with bulky dibenzhydryl substituents and their corresponding iron catalysts(Fe1~Fe4)were prepared by acid-catalyzed condensation of 2-R-6-dibenzhydryl-4-methylaniline(A1~A4)with 2,6-diacetylpyridine.The obtained iron catalysts were comprehensively characterized by FT-IR,mass spectrometry,and elemental analysis.These iron catalysts exhibited high polymerization activity(>10^(6) g·mol^(-1)·h^(-1)),capable of producing highly linear polyethylene with high molecular weights(3.3~515.7 kg·mol^(-1))and broad molecular weight distributions(polymer dispersity index PDI=1.83~17.26).It′s worth mentioning that the Fe4 catalyst can produce polyethylene with the highest molecular weight(515.7 kg·mol^(-1))at 30℃and exhibits the highest polymerization activity(9.96×10^(6) g·mol^(-1)·h^(-1))at 70℃.Notably,the polymerization temperature significantly affects both the molecular weight and molecular weight distribution of the resulting polyethylene.Higher temperatures lead to the formation of polyethylene with lower molecular weights and narrower molecular weight distributions.Interestingly,the o-aryl halogens have a significant impact on the molecular weight of polyethylene,with the atomic radius of the halogen substituents primarily determining the molecular weight of the polyethylene produced.

关 键 词：吡啶二亚胺铁催化剂 聚乙烯 高分子量 高度线性 卤素 

分 类 号：O63[理学—高分子化学]