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Ethylene Polymerization with Supported Vanadium‐Magnesium Catalyst: Number of Active Centers and Propagation Rate Constant
Author(s) -
Matsko Mikhail A.,
Bukatov Gennadii D.,
Mikenas Tatiana B.,
Zakharov Vladimir A.
Publication year - 2001
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(20010501)202:8<1435::aid-macp1435>3.0.co;2-#
Subject(s) - vanadium , ethylene , catalysis , polymerization , magnesium , reaction rate constant , chemistry , polymer chemistry , inorganic chemistry , organic chemistry , polymer , kinetics , physics , quantum mechanics
The data on the number of active centers in the ethylene polymerization with highly active supported vanadium‐magnesium catalyst (130 kg‐PE/g‐V·h·bar) were obtained by using 14 CO as a radioactive inhibitor. The number of active centers was found to attain 0.06 mol/mol‐V and the propagation rate constant equaled 2.2·10 4 L/mol·s (80°C). The effect of reversible deactivation of the catalyst in ethylene polymerization in the presence of hydrogen was studied. It was found that a part of the active centers containing vanadium‐polymer bonds transforms to a temporary inactive (dormant) state during the polymerization in presence of hydrogen that may explain the catalyst deactivation. As hydrogen is removed from the reaction medium, these centers transform to the active state again.