PROCESS FOR THE PREPARATION OF RANDOM COPOLYMERS

摘要

A process for the copolymerization of a mixture of monomers comprising propylene and 1-butene which comprises contacting the monomers and hydrogen in the gas phase in a single stage reaction zone, under polymerization conditions, with a catalyst system comprising (i) a solid catalyst precursor, which includes magnesium; titanium; a halogen which is chlorine, bromine, or iodine, or a mixture thereof; and a polycarboxylic acid ester containing two coplanar ester groups attached to adjacent carbon atoms; (ii) a hydrocarbyl aluminum cocatalyst; and (iii) a silicon compound containing at least one silicon-oxygen-carbon group, a temperature of from about 50.degree.C to about 90.degree.C, wherein: (a) the atomic ratio of aluminum to titanium is in the range of about 10 to about 300; (b) the molar ratio of aluminum to silicon compound is in the range of about 0.5 to about 10; (c) the propylene partial pressure is in the range of about 50 to about 450 psi; (d) the 1-butene partial pressure is in the range of about 10 to about 50 psi; (e) the hydrogen partial pressure is in the range of about 0.1 psi to about 80 psi; (f) the superficial gas velocity is in the range of about 1 to about 3 feet per second; and (g) the molar ratio of 1-butene to propylene is in the range of about 0.01:1 to about 0.4:1.