Patent ID: 9029599
Filing Date: 2015-05-12
Classification: C07C

Abstract:
1. A process for producing (meth)acrylic acid, comprising the step of repeating a crystallization operation “n” times to produce purified (meth)acrylic acid from crude (meth)acrylic acid, provided that the “n” is an integer 2 or more, wherein: the each crystallization operation comprises a crystallizing step of supplying a (meth)acrylic acid solution to a crystallizer to obtain a (meth)acrylic acid crystal, and a melting step of melting the (meth)acrylic acid crystal to obtain a (meth)acrylic acid melt; a polymerization inhibitor is not added to the (meth)acrylic acid melt obtained in the melting step of the first to n−1 a concentration of a polymerization inhibitor in the (meth)acrylic acid solution subjected to the crystallizing step of the first crystallization operation is adjusted so that a concentration of the polymerization inhibitor in the (meth)acrylic acid solution subjected to the crystallizing step of the n