Method of manufacturing (meth) acrylic acid

Abstract

A process for producing (meth)acrylic acid while preventing a polymerization of (meth)acrylic acid using a polymerization inhibitor solution, comprising the steps of: obtaining a (meth)acrylic solution containing formaldehyde from any step of the process for producing (meth)acrylic acid to use as a solvent of the polymerization inhibitor solution, and adding phenothiazine or derivatives thereof and/or hydroquinone or derivatives thereof to the (meth)acrylic solution containing formaldehyde to obtain polymerization inhibitor solution so that the polymerization inhibitor solution contains 0.1 mass % to 3 mass % of phenothiazine or derivatives thereof and/or 0.1 mass % to 10 mass % of hydroquinone or derivatives thereof, wherein the polymerization inhibitor solution contains 10 ppm to 5000 ppm (based on mass) of formaldehyde. The polymerization inhibitor solution used in the present invention is stable, generates little precipitate and is prepared using a low purity (meth)acrylic acid solution from the process for producing (meth)acrylic acid.

Dependencies are inferred from the claim text.