The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 10, 1983
Filed:
Jul. 21, 1982
Koji Nishihara, Wakayama, JP;
Takeshi Hashimoto, Wakayama, JP;
Shunsaku Tanaka, Wakayama, JP;
Katsuhiko Sato, Wakayama, JP;
Sugai Chemical Industry Co., Ltd., Wakayama, JP;
Abstract
A process for producing 4,4'-diphenyldisulfonic acid is disclosed, which comprises the steps of adding a sulfonating agent to molten diphenyl at a temperature within a range of 130.degree. to 145.degree. C., and when crystallization commences of 4,4'-diphenyldisulfonic acid within such temperature range, cooling the reaction mixture to a temperature within a range of 115.degree. to 127.degree. C., and letting the disulfonation reaction complete while the reaction mixture is maintained within the cooled temperature range. A process for producing monopotassium 4,4'-diphenyldisulfonate is also disclosed, in which steps are taken of adding a sulfonating agent to diphenyl, then controlling the sulfuric acid concentration to 45 to 55%, and while the reaction mixture is heated to at least 140.degree. C., adding at least a stoichiometric amount of a potassium salt of an inorganic acid.