US Patent 7342130 Method for producing acrylic acid

A method for producing acrylic acid, comprising (a) a absorption step of absorbing acrylic acid-containing gas obtained by oxidizing raw material gas in gas phase as crude acrylic acid-containing solution, (b1) a step of separating high boiling point components that separates the crude high boiling point components at a distillation column as (b) a step of purifying the acrylic acid-containing solution, and further, (c) a decomposition step of decomposing Michael adducts contained in the high boiling point components to prepare acrylic acid and (d) a collection step of collecting acrylic acid generated in the decomposition step (c), whereby the proportion of the amount of maleic acid to a sum of the sum of the maleic acid and maleic anhydride in the high boiling point components that are fed from the high boiling point component separation step (b1) to the decomposition step (c) satisfies a equation below: