Method for preparation of strong acid cation exchange resins
AssigneeRohm and Haas Company
InventorsWilliam Douglas Rohrbach, Bruce Maurice Rosenbaum
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Abstract
An improved process for preparing strong acid cation exchange resins by sulfonation of wet crosslinked copolymer in the absence of organic swelling solvents is disclosed. This process involves dewatering a crosslinked poly(vinylaromatic) copolymer to selected residual moisture levels of 3 to 35%, followed by non-solvent sulfonation, to provide strong acid cation exchange resins having enhanced physical stability and that are free of chlorinated-solvent contaminants.
Claims10
A method for preparing sulfonated crosslinked poly(vinylaromatic) copolymers comprising:
- (a) dewatering a crosslinked poly(vinylaromatic) copolymer prepared by aqueous suspension polymerization to provide a dewatered copolymer having a residual moisture content of 3 to 35 percent, based on weight of the dewatered copolymer;
- and
- (b) sulfonating the dewatered copolymer in the presence of 95 to 105 percent sulfuric acid, substantially in the absence of organic swelling solvent, at a temperature of 105° C. to 140° C. for 20 minutes to 20 hours.
A method for preparing sulfonated crosslinked poly(vinylaromatic) copolymers comprising:
- (a) dewatering a crosslinked poly(vinylaromatic) copolymer prepared by aqueous suspension polymerization with a centrifugal screener to provide a dewatered copolymer having a residual moisture content of 4 to 7 percent, based on weight of the dewatered copolymer;
- and
- (b) sulfonating the dewatered copolymer in the presence of greater than 96 and up to 99 percent sulfuric acid, substantially in the absence of organic swelling solvent, at a temperature of 125° C. to 135° C. for 2 to 6 hours.
Dependencies are inferred from the claim text.