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US 4,229,598 AGranted
Chemicals for treatment of PVC
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 short-stopper and retain effectiveness as a stabilizer in the finished polymer.
Claims1
A free radical inhibitor for terminating polyvinyl chloride polymerizations, said inhibitor prepared by a process comprising
- (1) methylating phenol with methanol in vapor phase at pressures of from about 110 to about 200 pounds per square inch gauge, temperatures of from about 400.degree. C. to about 700.degree. C. and a liquid hourly space velocity of from about 1 to about 15 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 an alkylating agent selected from the group consisting of isobutylene, isopentylene, isohexene, isooctene, cyclohexene or cyclopentene in the presence of a catalyst selected from the group consisting of sulfuric acid, sulfonic acids, sulfonated polystyrene resins crosslinked with divinylbenzene, and boron trichloride etherates 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.