METHOD OF EXTRACTING ACRYLIC ACID Russian patent published in 2011 - IPC C07C51/42 C07C51/44 C07C57/04 

FIELD: chemistry.

SUBSTANCE: invention relates to the technology of producing acrylic acid via gas-phase catalytic oxidation of propylene and/or acrolein, and specially to a step for extracting acrylic acid from aqueous solution formed during absorption of gaseous oxidation products with water. The method of extracting acrylic acid involves using a solvent to extract acrylic acid from its aqueous solution which contains acetic acid, formaldehyde, high-boiling impurities, distillation of the extract which contains acrylic acid, solvent, water and acetic acid, while feeding the solvent in form of condensate at low pressure with azeotropic distillation of water and solvent and extraction of the residue which contains acrylic acid and acetic acid, followed by distillation of the extracted residue which contains acrylic and acetic acid, while feeding condensate at low pressure in the presence of a polymerisation inhibitor with extraction of the desired acrylic acid and distillation of the distillate which contains acetic acid and acrylic acid, where distillation of the extract, which contains acrylic acid, solvent, water and acetic acid, is carried out while additionally feeding water to the step for distillation of the extracted residue which contains acrylic and acetic acid. The polymerisation inhibitor used is in form of an aqueous and the distilled distillate containing acetic acid and acrylic acid undergoes distillation at low pressure in the presence of a polymerisation inhibitor with extraction of acrylic acid and returning it to the step for distillation of the extracted residue containing acrylic and acetic acid.

EFFECT: high purity of the extracted acrylic acid and prevention of polymerisation of acrylic acid in equipment.

3 ex, 1 dwg