共聚单体诱导的C2对称茂金属催化丙烯聚合中的立体选择性增强

Comonomer-induced stereo-selectivity enhancement in a c2 -symmetric metallocene-catalyzed propylene polymerization.

作者信息

Ma Lin, Dong Jin-Yong

机构信息

CAS Key Laboratory of Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China; University of Chinese Academy of Sciences, Beijing, 100049, China.

出版信息

Macromol Rapid Commun. 2015 Apr;36(8):733-8. doi: 10.1002/marc.201400736. Epub 2015 Feb 26.

DOI:10.1002/marc.201400736

PMID:25721263

Abstract

Propylene polymerization is carried out with a C 2 -symmetric metallocene catalyst of rac-Et(Ind)2 ZrCl2 /MAO at 40 °C in the presence of a cyclo-triene of trans,trans,cis-1,5,9-cyclododecatriene ((E,E,Z)-CDT). Comonomer incorporations are rather low (<0.10 mol%). However, it is shown for the first time that the comonomer causes a noticeable increase in poly-propylene -isotacticity (>7% in [mmmm]). (E,E,Z)-CDT is speculated to coordinate to the metal center forming comonomer-complexed active sites in charge of the entire polymerization reaction with decreased activity however increased propylene -enantiomorphic selectivity.

摘要

在40℃下，使用rac-Et(Ind)2 ZrCl2 /MAO的C2对称茂金属催化剂，在反式、反式、顺式-1,5,9-环十二碳三烯((E,E,Z)-CDT)的环三烯存在下进行丙烯聚合。共聚单体的掺入量相当低(<0.10 mol%)。然而，首次表明共聚单体导致聚丙烯等规度显著增加([mmmm]中>7%)。推测(E,E,Z)-CDT与金属中心配位，形成负责整个聚合反应的共聚单体络合活性位点，活性降低，但丙烯对映体选择性增加。