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:
Oct. 26, 1999
Filed:
Mar. 02, 1998
Tetsuya Shiozaki, Saijo, JP;
Kenji Ikudome, Niihama, JP;
Sumitomo Chemical Company, Limited, Osaka, JP;
Abstract
A process for producing 2-hydroxy-4-methylthiobutanoic acid which includes conducting hydration and successive hydrolysis of 2-hydroxy-4-methylthiobutyronitrile in a reaction system containing 2-hydroxy-4-methylthiobutyronitrile and sulfuric acid, ammonium bisulfate being added to the reaction system at the time of the hydration and/or the hydrolysis, acquiring 2-hydroxy-4-methylthiobutanoic acid from the resulting organic layer, adding a water-miscible organic solvent to the by-produced aqueous layer to deposit ammonium sulfate, and separating and removing the ammonium sulfate from ammonium bisulfate, thereby permitting recycling and reusing of ammonium bisulfate, reduces the amount of sulfuric acid used, produces substantially no waste water containing sulfates and is of a low production cost and environmentally friendly.