多核催化：通过与双核助催化剂进行离子配对增强不同单中心烯烃聚合催化剂之间的链增长协同作用。

Polynuclear catalysis: enhancement of enchainment cooperativity between different single-site olefin polymerization catalysts by ion pairing with a binuclear cocatalyst.

作者信息

Abramo Graham P, Li Liting, Marks Tobin J

机构信息

Department of Chemistry, Northwestern University, Evanston, IL 60208-3113, USA.

出版信息

J Am Chem Soc. 2002 Nov 27;124(47):13966-7. doi: 10.1021/ja020870b.

DOI:10.1021/ja020870b

PMID:12440874

Abstract

A new multicenter ethylene polymerization process is described whereby two different single-site catalysts, one competent for producing vinyl-terminated oligomers or macromonomers and one competent for producing high-molecular weight ethylene-alpha-olefin copolymers, are held in close spatial proximity via ion-pairing with a dianionic binuclear bis-borate cocatalyst. Ethylene polymerizations mediated by stoichiometrically appropriate quantities of Me2Si(tBuN)(eta5-3-ethylindenyl)ZrMe2 and Me2Si(tBuN)(eta5-C5Me4)TiMe2 activated by the bis-borate cocatalyst [Ph3C+]2[1,4-(C6F5)3BC6F4B(C6F5)3-2] yield a more homogeneous polyethylene product when compared to control polymerizations using the mononuclear activator [Ph3C+][B(C6F5)4-]. The bulk and spectroscopic properties of the polymer produced using the binuclear activator are consistent with highly branched polyethylene.

摘要

描述了一种新的多中心乙烯聚合工艺，通过与双阴离子双核双硼酸盐助催化剂进行离子配对，使两种不同的单中心催化剂紧密相邻，其中一种能够生成乙烯基封端的低聚物或大分子单体，另一种能够生成高分子量乙烯- α -烯烃共聚物。与使用单核活化剂[Ph3C+][B(C6F5)4-]的对照聚合反应相比，由化学计量合适量的双硼酸盐助催化剂[Ph3C+]2[1,4-(C6F5)3BC6F4B(C6F5)3-2]活化的Me2Si(tBuN)(η5-3-乙基茚基)ZrMe2和Me2Si(tBuN)(η5-C5Me4)TiMe2介导的乙烯聚合反应产生了更均匀的聚乙烯产物。使用双核活化剂生产的聚合物的本体和光谱性质与高度支化的聚乙烯一致。