PRODUCTION OF (METH)ACRYLIC ACID

PROBLEM TO BE SOLVED: To enable efficient, simple and stable production of (meth)acrylic acid in no need of solvent, organic compound, metallic powder and the like without troubles caused by impurities by cooling an aqueous solution of (meth) acrylic acid to remove the impurities in a solid form. SOLUTION: When (meth)acrylic acid (A1 ) is extracted from an aqueous solution of (meth)acrylic acid (A1 ) produced by a vapor-phase catalytic oxidation, the (meth)acrylic acid (A1 ) aqueous solution is cooled to remove the precipitated solid substance and the remaining solution is subjected to the extraction separation. In an embodiment, the (meth)acrylic acid (A1 ) aqueous solution is introduced from a line 1 into a stirred tank A and cooled down to 5-50 deg.C, preferably to 20-40 deg.C under normal pressure. The (meth)acrylic aqueous solution containing the precipitated solid substance is introduced from a line 2 into a separator C to separate the solid substance from the aqueous solution and remove it through a line 4. The remaining aqueous solution is sent through a line 3 into an extraction column D and subjected to the extraction separation.