Process for purification of acrylic acid

In a process for producing acrylic acid in which propylene, acrolein or a mixture thereof are subjected to catalytic gas phase oxidation with a molecular oxygen-containing gas to obtain a mixed gas, contacting the mixed gas with water in an acrylic acid absorption tower to obtain an acrylic acid aqueous solution, and introducing the acrylic acid aqueous solution into an azeotropic separation tower for distillation of the acrylic acid aqueous solution along with the azeotrope solvent to separate acrylic acid from the acrylic acid aqueous solution, the improvement wherein said azeotrope solvent is a mixed solvent consisting of at least one solvent A selected from the group consisting of diethyl ketone, methyl propyl ketone, methyl isobutyl ketone, methyl-tert-butyl ketone and n-propyl acetate and at least one solvent B selected from the group consisting of toluene, heptane and methylcyclohexane whereby a mixture consisting substantially of acetic acid, water and the azeotrope solvent is distilled off from the top of the azeotropic separation tower and acrylic acid which is substantially free of acetic acid, water and the azeotrope solvent is obtained from the bottom of the tower.