Compound of organic siloxane, and catalyst system including the compound

Abstract

This invention provides an organosiloxane compound and catalyst system containing the organosiloxane compound for catalyzing olefin polymerization. The organosiloxane compound has a chemical formula of P(RI)Si(ORII)2, wherein P is cyclopentyl; RI is linear or branched C1-8 alkyl, or C6-10 cycloalkyl or aromatic group; RII is linear or branched C1-5 alkyl. The catalyst system comprises the organosiloxane compound, Ziegler-Natta catalyst and alkyl aluminum. The organosiloxane compound can coordinately donate electrons. The Ziegler-Natta catalyst system can reach the optimal catalytic efficiency, isotacticity and sensitivity to hydrogen simultaneously.

Description

technical field [0001] The invention provides an electron donor for a catalyst system for olefin polymerization, and a catalyst system comprising the electron donor. Specifically, the present invention relates to an organosiloxane compound, which is used as an electron donor, together with a titanium-based Ziegler-Natta catalyst and an aluminum alkyl to form a catalyst system for catalysis of olefins. Background technique [0002] The existing polyolefin catalysts for industrial production are still dominated by Zieg-Natta catalysts. After decades of development, due to the continuous improvement and development of catalysts, the development of polymerization processes and the improvement of polymer properties have been promoted. improve. [0003] The composition and preparation of Zieg-Natta catalyst systems for polypropylene are reported in many published literature methods, generally by MgCl 2 Loaded TiCl 4 The main catalyst and the co-catalyst are composed of organoal...

AI Technical Summary

Problems solved by technology

The Z-N catalyst system composed of dipropyldimethoxysilane and diisobutyldimethoxysilane is sensitive to the adjustment of the molecular weight of polypropylene by hydrogen, and is suitable for the preparation of polymers with lower molecular weight and higher MFR, and has higher catalyst activity. But its isotacticity is low, and the Z-N catalyst system composed of diphenyldimethoxysilane and cyclohexylmethyldimethoxysilane has high sensitivity to hydrogen and high isotacticity, and the catalyst activity of the composition is low

[0007] The inventors found that the silane electron donors connected to two different groups on the same silicon atom have a synergistic effect, but when two or more electron donors are used in combination, there is no synergistic effect

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