钒配合物及其催化乙烯与α-烯烃共聚的研究进展  

Progress in vanadium complex catalysts and their catalytic behavior toward copolymerization of ethylene withα-olefins

作　　者：张树[1] 张笑宇 王毅聪 吴一弦[1] Shu Zhang;Xiaoyu Zhang;Yicong Wang;Yixian Wu(State Key Laboratory of Chemical Resource Engineering,Beijing University of Chemical Technology,Beijing 100029,China)

机构地区：[1]北京化工大学化工资源有效利用国家重点实验室,北京100029

出　　处：《科学通报》2021年第30期3849-3865,共17页Chinese Science Bulletin

基　　金：国家自然科学基金(21774006,21634002)资助。

摘　　要：乙烯与α-烯烃(如丙烯、1-丁烯、1-己烯和1-辛烯等)共聚可制备乙丙橡胶、线形低密度聚乙烯、聚烯烃热塑弹性体和烯烃多嵌段共聚物等聚烯烃材料.在乙烯与α-烯烃共聚过程中,催化剂起着至关重要的作用.本文总结了用于催化乙烯与α-烯烃共聚的钒配合物催化剂及其催化性能的研究进展,包括钒配合物中钒的价态及配体的结构对乙烯与α-烯烃共聚的催化活性、单体竞聚率、共聚组成、序列分布、分子量及分子量分布的影响.钒(Ⅲ)配合物主要包括含氮杂环卡宾单齿配体、N^N或N^O双齿配体以及三齿或四齿配体的钒(Ⅲ)配合物,其中含有双齿配体的钒(Ⅲ)配合物催化乙烯与1-己烯共聚活性可高达8820 kg mol^(-1)h^(-1),配体空间位阻的增大阻碍α-烯烃的插入,使乙烯的竞聚率提高,α-烯烃的竞聚率降低,从而使α-烯烃的插入率降低;增加配体齿数,催化活性和共聚单体插入率均降低.钒(Ⅳ)配合物主要包括含胺类单齿或双齿配体、含N^O双齿配体和含O^N^N^O四齿配体的钒(Ⅳ)配合物,含N^O双齿配体钒(Ⅳ)配合物的催化活性通常低于含有相同配体钒(Ⅲ)配合物的催化活性.钒(Ⅴ)配合物主要包括含氮杂环卡宾配体的钒(Ⅴ)配合物、亚胺钒(Ⅴ)配合物以及含螯合芳氧基配体的钒(Ⅴ)配合物,其中含螯合芳氧基配体的钒(Ⅴ)配合物催化乙烯与丙烯共聚的催化活性可高达144400 kg mol^(-1)h^(-1),但共聚产物中丙烯结构单元含量不高于15%(mol);含氮杂环卡宾(NHC)配体的钒(Ⅴ)配合物可用于乙烯与丙烯拟活性共聚,制备出丙烯结构单元含量高的超高分子量乙烯-丙烯无规共聚弹性体.Ethylene-propylene rubber,linear low-density polyethylene and polyolefin elastomer,which are prepared by copolymerization of ethylene with α-olefins,have an important market share of the industry due to their excellent properties.Catalyst plays important role in the copolymerization of ethylene withα-olefins.Many vanadium complexes in the oxidation states of +3,+4 and +5 have been developed as precatalyst for the copolymerization.The progress of vanadium complex catalysts and their use in copolymerization of ethylene with α-olefins were reviewed.The effects of chelated ligands on the catalytic activity of catalysts,composition,molecular weight,molecular weight distribution and sequence of the resulting copolymers were discussed.Vanadium(Ⅲ)complexes are widely used since vanadium(Ⅲ)species are usually considered as active species in olefin coordination polymerization.Vanadium(Ⅲ)complexes bearing monodentate N-heterocyclic carbene(NHC)ligand or bidentate β-diketonate ligands have been used as precatalyst in copolymerization of ethylene with propylene,affording ethylene-propylene copolymers with high propylene content.Ethylene-propylene copolymers with ultra-high molecular weight were prepared by using vanadium(Ⅲ)complexes containing NHC ligand.Vanadium(Ⅲ)complexes bearing chelated bidentate N^N or N^O,etc.ligands show high catalytic activity up to 8820 kg mol^(-1) h^(-1) toward copolymerization of ethylene with 1-hexene.The introduction of bulky substitutes on the ligand results in an increase in the reactive ratio of ethylene and a decrease in the reactive ratio of 1-hexene,and thus a change in the sequence of monomer in the resulting copolymer.Vanadium(Ⅲ)complexes containing tridentate and tetradentate ligands display relatively lower catalytic activity than their analogues containing similar bidentate ligand.Most vanadium(Ⅳ)complexes display lower catalytic activity than vanadium(Ⅲ)complexes bearing similar ligands.Ethylene-propylene copolymer with high propylene content could be prepared by

关 键 词：钒配合物催化剂 乙烯与α-烯烃共聚 配位共聚 配体 

分 类 号：O641.4[理学—物理化学] TQ316.3[理学—化学] TQ426[化学工程—高聚物工业]