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US 6,552,231 B2Granted
Method for making dimethyl sulfone from dimethyl sulfoxide and hydrogen peroxide
AssigneeSloss Industries Corporation
InventorsCharles A. Jones, Joyce D. Friedrich, John C. Paschall, Wima K. Alwis
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Abstract
The present invention provides a process for synthesizing dimethyl sulfone by the oxidation of dimethyl sulfoxide with hydrogen peroxide.
Claims14
A method for making crystalline dimethyl sulfone comprising:
- (a) simultaneously adding dimethyl sulfoxide and an aqueous solution of hydrogen peroxide to a preheated, stainless steel reaction vessel precharged with an aqueous solution of dimethyl sulfone wherein the dimethyl sulfone and aqueous solution of hydrogen peroxide is added at a rate sufficient to maintain the reaction temperature below about 120° C.
- (b) distilling water from the reaction mixture;
- (c) then adding water to the reaction mixture to form a dilute reaction solution;
- (d) heating and filtering the heated dilute reaction solution;
- (e) cooling the dilute reaction solution to crystallize out the dimethyl sulfone;
- and
- (f) filtering or centrifuging the crystallized dimethyl sulfone.
4 more elements
A method for making flaked dimethyl sulfone comprising:
- (a) simultaneously adding dimethyl sulfoxide and an aqueous solution of hydrogen peroxide to a preheated, stainless steel reaction vessel precharged with an aqueous solution of dimethyl sulfone at a rate sufficient to maintain the reaction temperature below about 120° C.;
- (b) distilling water from thc reaction mixture;
- (c) cooling the reaction mixture to below 80° C.;
- (d) adjusting the pH of the reaction mixture to about between 8 and 9 with aqueous caustic;
- (e) distilling water from the reaction mixture at atmospheric pressure followed by distilling at a vacuum of at least 40 mm Hg and then followed by distilling at a vaccum of 20-30 mm Hg to provide a concentrated reaction mixture,
- (f) distilling dimethyl sulfone from the concentrated reaction mixture at about 160-175° C. as a colorless oil that solidifies upon cooling;
- and
- (g) flaking the dimethyl sulfone to provide a flowable dimethyl sulfone.
5 more elements
Dependencies are inferred from the claim text.