吡啶亚胺(胺)钒烯烃聚合催化剂

设计合成了一系列以吡啶二亚胺、吡啶胺-亚胺和吡啶二胺为螯合配体的三价钒配合物2a2e, 并通过红外和元素分析等技术手段对其进行了结构表征。 在助催化剂和再生活化剂的存在下, 这些催化剂展示出了高活性和良好的高温稳定性。 得到高相对分子质量、单峰分布聚乙烯表明聚合体系为单活性中心。 以吡啶二胺为螯合配体的配合物2e(2, 6-bis2, 6-(ⁱPr)₂PhNC(Me)]₂(C₅H₃N)VCl)在50 ℃下显示出的活性高达6.96 kg PE/mmol_V·h, 且在70 ℃时仍保持高的催化活性, 这表明双阴离子吡啶二胺能更好的保护催化活性中心。 此外, 这类三价钒催化剂能高活性催化乙烯-降冰片烯及乙烯-己烯共聚, 在温和条件下即可得到较高单体插入率(降冰片烯37.3%, 己烯4.8%)的共聚物。

Vanadium Complexes Containing Pyridylimine(amine) Ancillary Ligands for Olefin Polymerization

A series of vanadium(Ⅲ) complexes 2a2e bearing pyridyldiimine, pyridyl-imineamine and pyridyldiamine ligands was designed, synthesized, and characterized by IR and elemental analysis. Upon treatment with Et₂AlCl and CCl₃COOEt(ETA), these catalysts displayed high catalytic activity towards ethylene polymerization even at elevated reaction temperature, affording polymers with high relative molecular mass and unimodal relative molecular mass distributions, indicating the formation of a single active site during the polymerization. It was found that ligands structures exerted great influence on the polymerization behavior. Complex 2e(2, 6-bis2, 6-(ⁱPr)₂PhNC(Me)]₂(C₅H₃N)VCl) supported by dianionic pyridyldiamine showed an activity of 6.96 kg PE/(mmol_V·h) at 50 ℃ and the activity was well kept at the elevated temperature(70 ℃). Efficient copolymerization of ethylene with NBE or 1-hexene was also observed. Poly(ethylene-co-NBE) with the NBE content up to 37.7% was obtained by complex 2e under mild condition, and the incorporation of 4.8% 1-hexene was observed in poly(ethylene-co-1-hexene) by complex 2d.