Patent ID: 6166248
Filing Date: 2000-12-26
Classification: C07C

Abstract:
A process for isolating acrylic acid formed during catalytic gas phase oxidation of propene, which comprises:a) absorbing acrylic acid from the gas phase oxidation reaction mixture in an absorption stage using a first solvent, which solvent comprises at least one substituted or unsubstituted biphenyl, a substituted or unsubstituted diphenyl ether or dimethyl phthalate,b) removing a gas mixture in a condensation stage,c) cooling the gas mixture in a condensation stage,d) removing the condensed phase of the gas mixture from the condensation stage as acid water,e) removing the gaseous phase of the gas mixture from the condensation stage and recycling a least a portion thereof as circulated gas to the gas phase oxidation,wherein acrylic acid is extracted from the acid water in an acid water extraction stage using a second solvent which comprises at least one substituted or unsubstituted biphenyl, a substituted or unsubstituted diphenyl ether or dimethyl phthalate;f) desorbing the acrylic acid from the extract phase of the acid water extraction stage using air, nitrogen, or circulated gas;g) recycling the desorbed extracted acrylic acid from f) to step a).