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US 4,283,514 AGranted
Chemicals for termination of polyvinylchloride polymerizations
AssigneeConoco Inc.
InventorsDean R. Weimer, Charles M. Starks
Life of this patent
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Abstract
Butylation of a mixture of xylenols and trimethylphenols gives a product which is suitable for use as a stabilizer for polyvinyl chloride. The material can be added to the reactor during polymerization as a shortstopper and retain effectiveness as a stabilizer in the finished polymer.
Claims4
A method for terminating polyvinyl chloride polymerizations comprising injecting into the polymerization reactor at the desired level of conversion a free radical inhibitor obtained by,
- (1) methylating phenol with methanol in vapor phase at pressures of from about 1 to about 2500 pounds per square inch gauge, temperatures of from about 400.degree. C. to about 700.degree. C. and liquid hourly space velocity of from about 1 to about 15 in the presence of alumina or alumina containing catalyst and recovering a product stream therefrom;
- (2) distilling said product stream into desired fractions and retaining the fraction obtained at temperatures of from about 205.degree. C. to about 230.degree. C. at one atmosphere, and then;
- (3) alkylating the retained fraction with acidic catalysts at temperatures of from about 10.degree. C. to about 110.degree. C. and pressures of at least atmospheric while at a product fraction/alkylating agent weight ratio of from about 1/0.23 to about 1/1.85 respectively, then;
- (4) fractionally distilling the product of (3) and retaining the fraction obtained at temperatures of from about 110.degree. C. to about 200.degree. C. at 30 mm of mercury.
1 more element
Dependencies are inferred from the claim text.