Patent ID: 7041850

Claim:
A process for producing purified (meth)acrylic acid by subjecting crude (meth)acrylic acid containing maleic acids and aldehydes as impurities to distillation, said process comprising, prior to the distillation, the following steps: (A) adding hydrazines to the crude (meth)acrylic acid at a temperature of not less than a melting point of acrylic acid and not more than 50° C. to obtain a reaction solution containing a reaction product of the maleic acids and the hydrazines; (B) heat-treating the reaction solution obtained in the above step (A) at a temperature of 60 to 90° C. to convert the reaction product into a soluble substance; and (C) adding hydrazines to the thus heat-treated reaction solution obtained in the above step (B) at a temperature of not less than the melting point of acrylic acid and not more than 50° C. to obtain a soluble reaction product of the aldehydes and the hydrazines.