Purification of acrylic acid obtained by catalytic oxidation of propylene
AssigneeAtofina
InventorsMichel Fauconet, Marc Esch, Denis Laurent
Life of this patent
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Abstract
The method consists in extracting acrylic acid by countercurrent filtration washing of reaction gases by at least a hydrophobic absorbing heavy solvent, then recuperating the purified acrylic acid from the solution obtained at the end of this extracting step. As hydrophobic absorbing heavy solvent at least a hydrophobic aromatic compound is used having: a boiling point under atmospheric pressure between 260° C. and 380° C.; a crystallisation temperature less than 35° C. and a viscosity less than 10 mPa·s in a range of temperature between 30-80° C.
Claims17
A process for the purification of acrylic acid obtained by catalytic oxidation of propylene, comprising extracting acrylic acid in an extraction stage by countercurrentwise washing of reaction gases containing acrylic acid with at least one heavy hydrophobic absorption solvent, and recovering purified acrylic acid from the solution obtained on conclusion of said extraction stage,
- wherein said at least one heavy hydrophobic absorption solvent is a hydrophobic aromatic compound having:
- a boiling point at atmosphere pressure between 260° C. and 380° C.;
- a crystallisation temperature of less than 35° C.;
- and
- a viscosity of less than 10 mPa·s in a temperature range of 30-80° C., and
- wherein said hydrophobic aromatic absorption solvent is not an ester, and is not a mixture of biphenyl and diphenyl ether.
A process for the purification of acrylic acid obtained by catalytic oxidation of propylene, comprising extracting acrylic acid in an extraction stage by countercurrentwise washing of reaction gases containing acrylic acid with at least one heavy hydrophobic absorption solvent, and recovering purified acrylic acid from the solution obtained on conclusion of said extraction stage,
- wherein said at least one heavy hydrophobic absorption solvent is a hydrophobic aromatic compound having
- a boiling point at atmosphere pressure between 260° C. and 380° C.;
- a crystallisation temperature of less than 0° C.;
- and
- a viscosity of less than 10 mPa·s in a temperature range of 30-80° C.
A process for the purification of acrylic acid obtained by catalytic oxidation of propylene, comprising extracting acrylic acid in an extraction stage by countercurrentwise washing of reaction gases containing acrylic acid with at least one heavy hydrophobic absorption solvent, and recovering purified acrylic acid from the solution obtained on conclusion of said extraction stage,
- wherein said at least one heavy hydrophobic absorption solvent is a hydrophobic aromatic compound having:
- a boiling point at atmosphere pressure between 260° C. and 380° C.;
- a crystallisation temperature of less than 35° C.;
- and
- a viscosity of less than 10 mPa·s in a temperature range of 30-80° C., and
- wherein said hydrophobic aromatic absorption solvent is not a heavy carboxylic acid having a melting point of less than 30° C. and a boiling point of greater than 160° C., and
- wherein said hydrophobic aromatic absorption solvent is not a mixture of diphenyl and diphenyl ether.
A process for the purification of acrylic acid obtained by catalytic oxidation of propylene, comprising extracting acrylic acid in an extraction stage by countercurrentwise washing of reaction gases containing acrylic acid with at least one heavy hydrophobic absorption solvent, and recovering purified acrylic acid from the solution obtained on conclusion of said extraction stage,
- wherein said at least one heavy hydrophobic absorption solvent is a hydrophobic aromatic compound having:
- a boiling point at atmosphere pressure between 260° C. and 380° C.;
- a crystallisation temperature of less than 35° C.;
- and
- a viscosity of less than 10 mPa·s in a temperature range of 30-80° C., and
- wherein said hydrophobic aromatic absorption solvent does not yield impurities, due to hydrolysis, which will react with acrylic acid to form esters, and
- wherein said hydrophobic aromatic absorption solvent is not a mixture of diphenyl and diphenyl ether.
Dependencies are inferred from the claim text.