Process for production of acrylic acid.

摘要

Vapor phase catalytic oxidation of propylene into acrolein in the first step and then into acrylic acid in the second step has been improved (1) by utilizing as a diluent for the oxidation in the first step the effluent gas from the second step after the acrylic acid produced has been recovered therefrom and after it has been catalytically combusted and (2) by specifying operation conditions set in view of the recycle of the combusted "waste" gas. The improved process, embodying the present invention, has made it possible to produce a high concentration of acrylic acid as both gas and condensation and also to prolong the catalytic activity of a Mo-Bi composite oxide catalyst used for the first oxidation reaction.