In the production process for acrylic acid through catalytic vapour-phase oxidation of propene, acrylic acid is separated from the vapour-phase oxidation reaction mixture by means of an absorbing agent containing diphenyl, diphenyl ether or dimethyl phthalate and is also extracted from the vapour-phase oxidation acidic water by means of a solvent containing diphenyl, diphenyl ether or dimethyl phthalate.