Polymerization of ethylene and catalysts therefor

Abstract

Abstract Catalysts useful for making ethylene polymers by polymerizing ethylene alone or with a comonomer in the presence of hydrogen are described. They consist essentially of a mixture of (1) a bromo and/or ioda aluminum compound, preferably of the formula WHEREIN X is a halogen atom with at least one X being a bromine or iodine atom or a mixture of such compounds with each other and p is O or 1 and (2) a compound of a transition metal of Groups III-B, IV-B, V-B, VI-B, VII-B, VIII or 1-B of the Periodic Table, preferably vanadium. The combined bromine or iodine renders the catalyst composition more sensitive to hydrogen employed for molecular weight control so that the ethylene polymers which are obtained at a given hydrogen partial pressure have a higher melt index than those which are obtained with the same type of organoaluminum compound which does not contain the specified bromine or iodine constituent. The polymerization can be carried out in the presence of an inert solvent such as hexane, or a halogenated compound such as dichloromethane or dibromomethane, at a pressure from about 2 to about 10 atmospheres and employing an electrondonating compound such as t-butanol or water to modify the catalyst.

Inventors

• 👤 Edward H Mottus
• 👤 Morris R Ort

Bibliographic Details