| abstract |
PURPOSE: To obtain a high-purity α-substituted acetic acid with a simple operation in a short time in high purification yield, by reacting a specific α-substituted acetic acid with a weak alkali under shielded light condition and treating the resultant α-substituted acetic acid alkali salt with a decolorant. n CONSTITUTION: An α-substituted acetic acid selected from the compounds of formulas I-V (R 1 is H, halogen or 1-5C alkyl; R 2 is H, halogen 1-5C alkoxy, 1-5C alkylthio, CF 3 or one or more benzene rings) or an α-substituted acetic acid produced by the acid hydrolysis of the corresponding α-substituted acetonitrile under shielded light condition is made to react with a weak alkali selected from alkali metal bicarbonate, ammonia and magnesium hydroxide under shielded light condition. The obtained α-substituted acetic acid alkali salt is decolored with a decolorant to economically obtain the objective α- substituted acetic acid in the form of white crystal. The product has decreased color compared with the product produced by conventional process and the methanol solution of the product has transparent colorless appearance. n COPYRIGHT: (C)1989,JPO&Japio |