PRODUCTION OF MERCAPTOCARBOXYLIC ACID

• Main Authors: MIYATA KATSUJI, KAWASAKI NORIAKI, TAKETSUNA HIROTAKA, SAKAGUCHI YUTAKA
• Format: Patent
• Language: English
• Published: 03.08.1999
• Edition: 6
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; CHEMISTRY; METALLURGY; ORGANIC CHEMISTRY

PROBLEM TO BE SOLVED: To produce mercaptocarboxylic acids in high yield while suppressing the generation of by-product, thiodicarboxylic acids by reacting under a specific condition. SOLUTION: The objective mercaptocarboxylic acid of formula II is produced by reacting an unsaturated nitrile of formula I (R1 and R2 are each H, a 1-3C alkyl or phenyl; (n) is 0-3) with an alkali metal hydrosulfide, mixing the reaction liquid with an inorganic base, heating the mixture to remove the generated ammonia from the system, neutralizing the obtained reaction liquid with an acid, separating the product into liquid layers, separating the oil layer composed of mercaptopropionic acid, extracting mercaptocarboxylic acid dissolved in the water layer with an organic solvent and recovering the mercaptocarboxylic acid from the organic solvent layer and/or the oil layer or extracting the neutralized liquid with an organic solvent, separating into layers, separating the mercaptocarboxylic acid from the organic solvent layer and getting a high-purity aqueous solution of inorganic salt from the water layer after extraction.