Patent Number: 6,252,111

Title: Method for producing sulfonimide or its salt

Abstract: The invention relates to a method for producing a sulfonimide or its alkali metal salt. The method includes the steps of (a) reacting a precursory salt of the sulfonimide with a base contained in a basic aqueous solution, thereby producing a first aqueous solution containing the alkali metal salt and an amine; (b) removing the amine from the first aqueous solution to obtain a second aqueous solution containing the alkali metal salt; and (c) crystallizing the alkali metal salt in the second aqueous solution. The base is potassium hydroxide, sodium hydroxide or lithium hydroxide. The base is added to the second aqueous solution to generate the crystallization. The precursory salt is formed when the sulfonimide is reacted with a tertiary amine or a heterocyclic amine. The alkali metal salt is produced easily and economically in an industrial scale production with high purity and high yield.

Inventors: Sakai; Shigenori (Yamaguchi, JP), Takase; Hironari (Saitama, JP), Sakaguchi; Hiroaki (Yamaguchi, JP)

Assignee: Central Glass Company, Limited

International Classification: C07C 303/00 (20060101); C07C 303/40 (20060101); C07C 311/48 (20060101); C07C 311/00 (20060101); C07C 303/34 (); C07C 303/44 ()

Expiration Date: 06/26/2018