Patent ID: 7557246
Filing Date: 2009-07-07
Classification: C07C

Abstract:
1. A process for production of (meth)acrylic acid, whereby first a crude (meth)acrylic acid is produced and this crude (meth)acrylic acid is then continuously purified, wherein the continuous purification of the crude (meth)acrylic acid comprises the following process steps: a) in a composition comprising (meth)acrylic acid and impurities, precipitating the impurities from the composition in crystalline form wherein the impurity comprises maleic acid anhydride, and wherein the maleic acid anhydride is hydrolyzed to a portion of at least about 50 mol %, based on the total amount of the maleic acid anhydride comprised in the composition before the staff of the hydrolysis, with formation of maleic acid and/or fumaric acid, wherein maleic acid and/or fumaric acid precipitate in crystalline form from the composition; b) separating the crystalline maleic acid and/or fumaric acid precipitated from the composition.