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US 4,065,475 AGranted
Process for preparing CIS-epoxysuccinic acid salts of high purity
AssigneeToray Industries, Inc.
InventorsKazuo Hosoi, Norio Kawabe, Masaji Ohno
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Abstract
High purity cis-epoxysuccinic acid and salts thereof are economically and systematically prepared by contacting an aqueous solution, obtained by reacting a maleic acid salt and hydrogen peroxide in the presence of a tungstate or molybdate catalyst under a specified condition, with a strongly basic Type II anion exchange resin.
Claims8
A continuous process for preparing a highly pure cis-epoxysuccinic acid salt, comprising the steps of:
- a. conducting an epoxidation reaction by contacting and reacting a maleic acid salt with hydrogen peroxide in the presence of a tungstate or molybdate catalyst to form an aqueous epoxidation reaction solution;
- b. contacting said aqueous epoxidation reaction solution with a Type II strongly basic anion exchange resin in the neutralized form at a pH lower than about 7 to selectively adsorb said catalyst;
- c. contacting said resin with an alkali metal hydroxide to recover said catalyst in the form of an aqueous solution,
- d. treating said recovered catalyst solution with a calcium ion source at a pH of about 7.0-8.5, and
- e. adding maleic acid or maleic anhydride and hydrogen peroxide into said recovered catalyst solution to form another epoxidation reaction solution whereby the catalyst is recycled and the resin is regenerated to provide a continuous process.
2 more elements
A continuous process for preparing a highly pure cis-epoxysuccinic acid salt, comprising the steps of:
- a. conducting an epoxidation reaction by contacting and reacting a maleic acid salt with hydrogen peroxide in the presence of a tungstate or molybdate catalyst to form an aqueous epoxidation reaction solution;
- b. contacting said aqueous epoxidation reaction solution with a Type II strongly basic anion exchange resin in the neutralized form at a pH lower than about 7 to selectively adsorb said catalyst;
- c. contacting said resin with an alkali metal hydroxide to recover said catalyst in the form of an aqueous solution;
- d. treating said recovered catalyst solution with calcium sulfate at a pH of about 7.0-8.5 so as to precipitate calcium racemic tartrate, and then
- e. adding maleic acid or maleic anhydride and hydrogen peroxide into said recovered catalyst solution to form another epoxidation reaction solution, whereby the catalyst is recycled and the resin is regenerated so as to provide a continuous process.
2 more elements
Dependencies are inferred from the claim text.