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High activity mixed metal alkyl cocatalysts for α‐olefin polymerization
Author(s) -
Bacskai R.
Publication year - 1988
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1988.070350204
Subject(s) - alkyl , propene , olefin fiber , polymerization , stereospecificity , metal , chemistry , polymer chemistry , alkylation , catalysis , magnesium , aluminium , ziegler–natta catalyst , polymer , organic chemistry
High activity α‐olefin polymerization catalysts are generally obtained by mixing MgCl 2 ‐supported TiCl 4 (MgCl 2 /TiCl 4 ) with an aluminum trialkyl cocatalyst. Surprisingly, AlEt 2 Cl, which is the preferred cocatalyst in polymerizations employing nonsupported Ti compounds, is a poor cocatalyst when used with MgCl 2 /TiCl 4 . It was found that in propylene and 1‐butene polymerizations, using different MgCl 2 /TiCl 4 catalysts, the cocatalyst activity of AlEt 2 Cl can be greatly improved by the addition of a magnesium or lithium alkyl. The mixed metal alkyl obtained from AlEt 2 Cl and MgBu 2 is a particularly effective cocatalyst always yielding more polymer, of about the same stereospecificity, than the conventional aluminum trialkyls. The exact nature of the mixed metal alkyl cocatalysts is not known, but the available evidence argues against in situ aluminum trialkyl formation resulting from the alkylation of AlEt 2 Cl by the second metal alkyl.