PURIFICATION PROCESS OF ACRYLIC ACID OBTAINED BY CATALYTIC OXIDATION OF PROPYLENE

摘要

By employing the process according to the present invention, purification of acrylic acid obtained by catalytic oxidation of propylene and extracted by countercurrent wash of reaction gases with at least one hydrophobic solvent in extraction column (C1) is ensured. For this purpose a flow (5), obtained at the extraction column (C1) bottom is distilled in distillation column (C3) so as to obtain a very pure flow (6) of acrylic acid at upper end of the distillation column (C3) and to enable the transfer of acrylic acid to a bottom flow (7); the bottom flow (7) is then conducted as a feed to bottom part of a distillation column (C4) from the side of which there is withdrawn a flow (9) rich in maleic acid anhydride and contaminants with a boiling point lying between the acrylic acid boiling point and boiling point of heavy solutions and notably on a tray lying between the feed place and the distillation column upper end; a flow (8) rich in acrylic acid that is returned back in the distillation column (C3) is distilled off at the distillation column (C4) top; and a flow (1) containing heavy solvents and heavy contaminants and that is recycled to the extraction column (C1) upper end is obtained at the distillation column (C4) bottom.