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:
Nov. 01, 2005
Filed:
Jun. 19, 2002
Tadayoshi Kawashima, Himeji, JP;
Yoshitake Ishii, Himeji, JP;
Kei Hamamoto, Himeji, JP;
Souichi Yamada, Himeji, JP;
Tetsuya Kajihara, Himeji, JP;
Tadayoshi Kawashima, Himeji, JP;
Yoshitake Ishii, Himeji, JP;
Kei Hamamoto, Himeji, JP;
Souichi Yamada, Himeji, JP;
Tetsuya Kajihara, Himeji, JP;
Nippon Shokubai Co., Ltd., Osaka, JP;
Abstract
This invention discloses a method for producing maleic anhydride comprising an azeotropic distillation step to dehydrate a crude maleic acid-containing aqueous solution, which method is characterized by as an azeotropic solvent (1) using an organic solvent exhibiting a maximum dissolving concentration of the organic solvent in water in the range of 0.1-5% by weight at a temperature of 20° C. According to this invention, it is made possible to prevent the occurrence of a blocking substance, allow a continuous operation for a long time, and remove by-produced acid components by a process of distillation for azeotropic dehydration.