Patent ID: 7332624

Claim:
A method for the production of acrylic acid which comprises the steps of: (a) supplying one or more gas components selected from the group consisting of propylene, propane and acrolein to a reactor for catalytic gas phase oxidation, (b) obtaining an acrylic acid-containing gas by catalytic gas phase oxidation, (c) introducing said acrylic acid-containing gas and supplying an aqueous absorbing solvent into an acrylic acid absorbing column, whereby an aqueous acrylic acid-containing solution is absorbed onto said acrylic acid absorbing column (d) obtaining said aqueous acrylic acid-containing solution absorbed onto said acrylic acid absorbing column, (e) obtaining crude acrylic acid from said aqueous acrylic containing solution in an azeotropic dehydration column by dehydration; (f) introducing a polymerization inhibitor to said azeotropic dehydration column at any point between a point for supplying said aqueous acrylic acid containing solution and a point for supplying a reflux and not including the point for supplying said aqueous acrylic acid containing solution material and the point for supplying the reflux; (g) optionally removing a low boiling substance from said aqueous acrylic acid-containing solution by using an azeotropic distillation column, (h) obtaining acrylic acid and a high boiling substance-containing solution by removing the high boiling substance from said crude acrylic acid, subsequently (i) recovering acrylic acid by thermally decomposing an acrylic acid oligomer contained in said high boiling substance-containing solution, and (j) supplying the acrylic acid recovered by thermally decomposing said acrylic acid oligomer from step (i) to said azeotropic dehydration column.