Abstract: A process control scheme for temporarily slowing or killing the production of polypropylene while idling the reactor using a fourth generation catalyst system containing a solid magnesium chloride supported titanium tetrachloride catalyst component containing an internal strong electron donor in combination with a silicon compound, and an organoaluminum compound (cocatalyst) is disclosed. This process entails the introduction of an amount of an external strong electron donor to the ongoing polymerization reaction. The polymerization reaction can be restarted by introducing an additional amount of the organoaluminum compound.
Type:
Grant
Filed:
March 30, 1993
Date of Patent:
May 9, 1995
Assignee:
Huntsman Polypropylene Corporation
Inventors:
Horst K. Seeger, Yao-Ching Liu, LeVoy G. Haight, Luis A. Pagan, Kimberly R. Payne, Jeffrey J. Vanderbilt