Patent ID: 7048834

Claim:
A method for purification of acrylic acid, which comprises the steps of: a) providing a crude acrylic acid having a concentration ratio of furfural to acrolein by weight that is adjusted so as to satisfy the following equation: 3≦(furfural concentration by weight)/(acrolein concentration by weight)≦100; then b) charging the crude acrylic acid with an aldehyde treatment chemical, with the aldehyde treatment chemical comprising a hydrazine compound; then c) reacting the hydrazine compound with aldehydes of the crude acrylic acid such that, after said step of reacting and prior to a step of distilling the crude acrylic acid, a concentration of said hydrazine compound in said crude acrylic acid is not more than 100 ppm by weight; and then d) distilling the crude acrylic acid containing said furfural and acrolein as impurities.