Gas phase ethylene polymerization over SiO₂-supported organosilyl chromate UCC S-2 catalyst using a high-speed stirred-autoclave reactor

Abstract

Although an important industrial catalyst for producing high density polyethylene, the SiO₂-supported organosilyl chromate UCC S-2 catalyst has not been fully investigated compared with the SiO₂-supported oxo chromium Phillips catalyst. In this work, gas phase ethylene polymerization by S-2 catalysts (Cat-1, Cat-2, and Cat-3) was carried out in a high-speed stirred-autoclave reactor. The effects of temperature, time, and pressure on kinetics, activity, and product properties were studied. All kinetics were typical built-up types with slow decay. Compared to the simple physical mixtures of Cat-1 and Cat-2, Cat-3 showed higher activity and its product had a broader molecular weight distribution, indicating new active species induced during blending of Cat-1 and Cat-2 in n-hexane. The innovation by a simple catalyst technology created a new application to meet market demands.

Key words： UCC S-2 catalyst; Al-alkyl co-catalyst; gas-phase ethylene polymerization; high density polyethylene

Acknowledgments

The authors were grateful to the Key Projects in the National Science & Technology Pillar Program during the 11th Five-Year Plan Period (2007BAE50B04) and Qilu Branch Co., SINOPEC for the financial support.

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