JPH05339220

• Main Authors: OYOSHI HAJIME, SAKAMOTO NAOYA
• Format: Patent
• Language: English
• Published: 21.12.1993
• Edition: 5
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; CHEMISTRY; METALLURGY; ORGANIC CHEMISTRY

PURPOSE:To industrially and effectively remove by-produced colored substances and purify the keto acid derivative by adding a hydrogenation catalyst to a reaction solvent containing the crude keto acid derivative obtained from a N,N-dialkyl-m-aminophenol and phthalic acid and subsequently hydrogenating the crude keto acid derivative. CONSTITUTION:When a keto acid derivative of the formula (R , R are 1-6C alkyl) is obtained by reacting a N,N-dialkyl-m-aminophenol with phthalic anhydride and subsequently purified, the crude colored keto acid derivative of the formula containing a small amount of colored substances such as rhodamine is dissolved in a reaction solvent, mixed with a hydrogenation catalyst, hydrogenated in a reaction solvent and subsequently subjected to recrystallization, etc., to recover the keto acid derivative from the reaction solution. The method is advantageous, since an alkali, etc., is not used, and neutralized effluent water, etc., is not discharged. The keto acid derivative having a good color tone can be obtained by the foregoing simple process.