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Study of the effect of hydrogen in propylene polymerization with the MgCl2-supported ziegler-natta catalyst—part 1. Kinetics of polymerization

✍ Scribed by L.A. Rishina; E.I. Vizen; L.N. Sosnovskaja; F.S. Dyachkovsky

Publisher
Elsevier Science
Year
1994
Tongue
English
Weight
285 KB
Volume
30
Category
Article
ISSN
0014-3057

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✦ Synopsis

Propylene polymerization was investigated with the TiC14/MgCI 4 supported catalyst with the stereoregulating donor pair dibutylphtalate (DBPH)/triethoxyphenylsilane (TEPS) in heptane with A1Et 3 as cocatalyst in the presence of hydrogen. It was shown that there is an activation effect by the influence of hydrogen. The removal of hydrogen from the polymerization medium results in an immediate disappearance of activation. However, the deactivation of the system is reversible, and it is possible to repeat the activation effect by hydrogen more than once. It was found that the value of the activation energy is the same in the presence of hydrogen and without it and is equal to 11 kcal/mol. From the experimental results it is concluded that the maximum number of active centres is realized in the catalytic system in the presence of hydrogen, but a value of the propagation rate constant is not changed. It was also found that in the presence of hydrogen the system's decay follows the bimolecular law of active centres deactivation.

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