METHOD FOR PRODUCING (METH)ACRYLIC ACID

摘要

PROBLEM TO BE SOLVED: To provide a method for producing (meth)acrylic acid capable of attaining the longer-term continuous operation for the production through suppressing the adverse effect of byproducts in the distillation step. SOLUTION: This method for producing (meth)acrylic acid involves introducing a (meth)acrylic acid-containing liquid with <=0.1 mass% in the concentration of glyoxal (including its hydrate) contained therein into a distillation column. The other version of this method comprises the step of obtaining an aqueous solution of (meth)acrylic acid by contacting a collecting liquid with a product obtained using propylene and/or acrolein or the like and a circulating line through which the collecting liquid separated from the effluent resulted from separating the (meth)acrylic acid from the above aqueous solution is circulated; wherein part or the whole of the collecting liquid in the circulating line is separated into a non-permeated liquid and a permeated liquid by the use of a reverse osmosis membrane and part or the whole of the permeated liquid is circulated as the collecting liquid.