US 6,184,428 B2 · Catalyst and process for ethylene oligomerization

Abstract

A catalyst and a process are provided for oligomerizing ethylene. A heterogeneous catalyst system comprises: (1) a chelating ligand, preferably 2-diphenyl phosphino benzoic acid (DPPBA); (2) a nickel precursor, preferably nickel chloride hexahydrate (NiCl2.6H2O); (3) a catalyst activator, preferably sodium tetraphenylborate (NaBPh4); and (4) silica. A 1:1:1 molar ratio of Ni:DPPBA:BPh4 catalyst components are fixed on a silica support using low-temperature fixation. The catalyst components are dispersed in a diluent, preferably ethanol, and silica is added. The ethanol is evaporated using freeze-drying equipment to form a silica-supported catalyst system. The silica-supported catalyst is slurried in ethanol in a reactor, and ethylene is added. The reactor pressure and temperature are maintained at about 725 psig and 100° C., respectively, for about two hours. The oligomer product formed has a narrower weight percent distribution, typically having about 96 weight percent C4's to C10's, compared to product formed using a homogeneous catalyst system.

Claims24

Dependent claims

A process for ethylene oligomerization, comprising the steps of:

maintaining a supported nickel catalyst as a slurry in a liquid material;
said supported nickel catalyst consisting of a reaction product of 2-diphenylphosphino benzoic acid (DPPBA), nickel chloride hexahydrate (NiCl2.6H2O) and sodium tetraphenylborate deposited upon silica particles;
dissolving ethylene into the liquid material of said supported nickel catalyst slurry;
controlling said slurry temperature from about 80° C. to about 120° C. for a time sufficient to oligomerize ethylene to produce lower alpha-olefins.

1 more element

Dependencies are inferred from the claim text.

Catalyst and process for ethylene oligomerization

Life of this patent

Catalyst and process for ethylene oligomerization

Life of this patent

Abstract

Claims24