Patent ID: 8704000
Filing Date: 2014-04-22
Classification: C07C

Abstract:
1. A method for crystallizing (meth) acrylic acid comprising the steps of: (1) crystallization operation, (2) sweating operation and (3) melting operation, wherein (1) the crystallization operation comprises depositing an (meth)acrylic acid crystal, (2) the sweating operation comprises sweating the (meth)acrylic acid crystal to obtain an (meth)acrylic acid crystal containing a reduced amount of impurities, and (3) the melting operation comprises melting a part of the (meth)acrylic acid crystal containing a reduced amount of impurities to obtain a molten liquid melted after initiation of the melting and, wherein (a) a polymerization inhibitor is added to the molten liquid melted after initiation of the melting and (b) the molten liquid containing the polymerization inhibitor is circulated and fed to the (meth)acrylic acid crystal containing a reduced amount of impurities until all of the (meth)acrylic acid crystal is melt.