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Kinetic study of a highly active MgCl 2 ‐supported Ziegler–Natta catalyst in liquid pool propylene polymerization. II. The influence of alkyl aluminum and alkoxysilane on catalyst activation and deactivation
Author(s) -
Shimizu Fumihiko,
Pater Jochem T. M.,
Van Swaaij Wim P. M.,
Weickert Günter
Publication year - 2002
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.10236
Subject(s) - catalysis , alkyl , polymerization , polymer chemistry , ziegler–natta catalyst , chemistry , natta , materials science , polymer , organic chemistry
Abstract The influence of alkyl aluminum and alkoxysilane on the kinetics in liquid pool propylene batch polymerization was investigated with a highly active Ziegler–Natta catalyst system that consisted of MgCl 2 /TiCl 4 /diester–alkoxysilane/AlR 3 . In this study, diethyl phthalate and t ‐BuEtSi(OMe) 2 were used as a diester and an alkoxysilane, respectively. The catalyst activity depended on the concentration of the alkyl aluminum when it came into contact with the catalyst. In addition, alkoxysilane as an external donor had a role in activating the catalyst. With respect to activity decay, the overreduction of Ti did not seem to be the cause. Instead, the decay rate decreased with an increasing alkoxysilane/catalyst ratio. This implied that activity decay was caused by the formation of dormant sites after 2,1‐misinsertion of propylene. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2669–2679, 2002