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US 4,232,140 AGranted
Process for polymerizing olefins
AssigneeCities Service Company
InventorMorris R. Ort
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AssigneeCities Service Company
InventorMorris R. Ort
Estimating the term…
Trichlorofluoromethane is used as a promoter in the polymerization and copolymerization of ethylene with supported Ziegler-type vanadium compound/alkylaluminum compound catalysts in the presence of hydrogen. The use of the promoter leads to the formation of non-rubbery, semi-crystalline polymers in high yields, does not alter the basic molecular weight distribution of the polymers, permits independent control of molecular weight by hydrogen, and imparts no significant level of halogen to the product.
In a process for preparing non-rubbery, semicrystalline polymers and copolymers by contacting an ethylene-containing stream with a supported catalyst comprising (a) a vanadium chloride and (b) at least one alkylaluminum compound of the formula R.sub.n Al(OR).sub.3-n, wherein R is an alkyl group containing 1-12 carbons and n is 0.5-3.0, on (c) an anhydrous inert inorganic support material under gas-phase polymerization conditions in the presence of hydrogen, the improvement which comprises conducting the polymerization in the presence of trichlorofluoromethane.
Dependencies are inferred from the claim text.
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Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond: ethene
Synthetic resins or natural rubbers -- part of the class 520 series: monomer polymerized in vapor state in presence of transition metal containing…
Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
Technical subjects covered by former uspc cross-reference art collections [xracs] and digests
Term ended 4 Nov 1997 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
The invention is an improved process for preparing non-rubbery, semi-crystalline polymers and copolymers by contacting an ethylene-containing stream with a supported catalyst comprising (a) a vanadium chloride and (b) at least one alkylaluminum compound of the formula R.sub.n Al(OR).sub.3-n, wherein R is an alkyl group containing 1-12 carbons and n is 0.5-3.0, on (c) an anhydrous inert inorganic support material under gas-phase polymerization conditions in the presence of hydrogen. In accordance with the invention, improved yields are obtained by conducting the polymerization in the presence of trichlorofluoromethane as a promoter.
The ethylene-containing stream employed in the practice of the invention may contain ethylene as the sole monomer, or it may comprise a mixture of ethylene and one or more alpha-olefins containing 3-8 carbons, e.g., propylene, butene-1, hexane-1, etc.
The vanadium chloride of the catalyst may be any of the vanadium chlorides conventionally used in Ziegler-type catalyst systems, e.g., vanadium tetrachloride and/or vanadium trichloride. However, it is preferably vanadium oxytrichloride.
The following examples are given to illustrate the invention and are not intended as a limitation thereof.
Charge a small fluid-bed catalyst preparation unit with a dehydrated silica gel having a particle size of about 50-65 microns and containing about 1.4 mmol of available hydroxyl groups per gram on its surface. Fluidize the silica gel with dry, oxygen-free nitrogen at a temperature of about 40.degree. C. while adding a hexane solution of diethylaluminum ethoxide (DEAE) dropwise onto the silica gel to provide one millimole of DEAE per gram of silica gel. After completing the DEAE addition, evaporate the hexane from the fluid bed.
Prepare a polymerization catalyst by: