Catalyst for regulating the molecular weight distribution of ethylene polymers

Claim 1

In a process for homopolymerizing ethylene, or copolymerizing ethylene with one or more alpha olefins containing from 3 to 8 carbon atoms, with a catalyst system comprising (A) a solid catalyst precursor consisting essentially of (1) a solid, particulate, porous, inorganic carrier, as support for (2) the reaction product of (a) a vanadium trihalide and (b) an electron donor, and (3) a boron halide or alkylaluminum modifier, (B) an alkylaluminum cocatalyst, and (C) a halohydrocarbon polymerization promoter, the improvement which comprises treating solid catalyst precursor (A) with an oxygen-containing molecular weight distribution regulator selected from the group consisting of compounds having the formulas A--R--B and R.sup.1 --B wherein: R is a divalent hydrocarbon radical free of aliphatic unsaturation containing from 1 to 14 carbon atoms, R 1 is a heterocyclic ring free of aliphatic unsaturation containing from 2 to 14 carbon atoms and at least one oxygen or nitrogen atom, and A and B are each selected from the group consisting of: --OH, --R.sup.1, --OR.sup.2, COOR.sup.2, --NR.sup.3 R.sup.4 and wherein: R 1 is as defined above, R 2 is a monovalent hydrocarbon radical free of aliphatic unsaturation containing from 1 to 14 carbon atoms, and R 3 and R 4 are individually hydrogen or monovalent hydrocarbon radicals free of aliphatic unsaturation containing from 1 to 14 carbon atoms, with the proviso that at least one of A and B must be --OH or --COOR 2 , but both A and B cannot be --OH.