Acrylic acid recovery utilizing ethyl acrylate and selected co-solvents

A method of recovering acrylic acid comprising:

• (a) providing a feed stream containing acrylic acid, water, acetic acid, ethyl acrylate and an organic co-solvent selected from the group consisting of toluene, heptane, 1-heptene, methylcyclohexane, cycloheptane, cycloheptadiene, cycloheptatriene, 2,4-dimethyl-1,3 pentadiene, methylcyclohexene and methylenecyclohexene to a distillation column, wherein the weight ratio of ethyl acrylate to said organic co-solvent is from about 80:20 to about 95:5;
• and
• (b) azeotropically distilling said feed stream to provide a residue stream, the preponderant component of which is acrylic acid.

A method of recovering acrylic acid from a mixture comprising acrylic acid, water and acetic acid comprising:

• (a) extracting acrylic acid from said mixture with a solvent mixture comprising ethyl acrylate as the preponderant component thereof and an organic co-solvent selected from the group consisting of toluene, heptane, 1-heptene, methylcyclohexane, cycloheptane, cycloheptadiene, cycloheptatriene, 2,4-dimethyl-1,3 pentadiene, methylcyclohexene and methylenecyclohexene to form an extracted composition;
• (b) azeotropically distilling said extracted composition to recover acrylic acid having a concentration of at least about 96%, and
• (c) subsequently directing the crude acrylic acid to a distillation column wherein a light ends fraction is taken overhead, a heavy ends fraction is taken from the base of the tower, and a side stream is removed from a point below the feed tray, said stream having an acrylic acid concentration of at least about 99% purity.

A method to produce acrylic acid having about or greater than 99.8% purity, comprising:

• oxidation of propylene or acrolein with air forming a reaction product of acrylic acid mixture wherein the reaction product is quenched and subsequently extracted with a mixture of EA/Co-Solvent;
• the organic phase is subjected to a solvent recovery step wherein the resultant extractant is distilled in a solvent recovery column to obtain an overhead stream of solvent and water and a residue stream of acrylic acid and other minor components, which residue is fed to a distillation column having a side stream, and the side stream product subsequently purified to obtain acrylic acid having about or greater than 99.8% acrylic acid.