Arkema France

Elf Atochem S.a.

Arkema Inc.

Atofina

Denis Laurent

Michel Fauconet

Marc Esch

Jean-Francois Devaux

Mireille Stojanovic

Jean-François Devaux

Yves Samuel

The present invention relates to the manufacture of bioresourced polymer-grade acrylic acid from glycerol. The polymer grade acrylic acid produced has limited content of certain impurities harmful to polymerization processes, such as, total aldehydes, protoanemonin, maleic anhydride and nonphenolic polymerization inhibitors. The invention also relates to the use of the bioresourced acrylic acid obtained for manufacture of superabsorbents or for manufacture of polymers or copolymers using amide or ester derivatives of the bioresourced acrylic acid.

Process for producing bio-resourced polymer-grade acrylic acid from glycerol

The present invention relates to a method for purifying (meth)acrylic acid obtained by catalytic or redox oxidation of a gaseous substrate constituting propane, propylene, acrolein, isobutane, isobutene, tert-butyl alcohol and/or (meth)acrolein or mixtures thereof by sending the gaseous reaction mixture to the bottom of a countercurrent absorption column (C) which is supplied at the top with at least one type of hydrophobic heavy solvent, sending the flow () from the bottom of column (C) to a separation column (C). Column (C) is operated at a flow rate of heavy solvent of from 3 to 5.6 times the flow rate of the (meth)acrylic acid in the gaseous reaction mixture and the rectifying column used as a separation column (C) is operated with the feed at the top and without reflux.

Method for purifying (meth)acrylic acid obtained by oxidizing a gaseous substrate

The gas reaction mixture (), formed of propylene, if the case arises, of ultimate oxidation products, of acrylic acid, of acrolein, of steam, of acetic acid and of heavy products, is sent to the bottom of an absorption column (C) fed countercurrentwise at the top with a heavy hydrophobic absorption solvent. The gas flow (), formed of propylene and of ultimate oxidation products, of major amounts of water and acetic acid, and of acrolein, is obtained at the top of (C) and a flow (), formed of acrylic acid, of the heavy solvent, of heavy products and of minor amounts of acetic acid and of water, is obtained at the bottom of (C). The flow () is sent to a heat exchanger (C), where it is brought into contact with a descending liquid stream (), fed at the top of (C), composed of the recycling of a portion of the flow (), cooled beforehand, from the bottom of (C), in order to obtain, at the top, a gas flow () comprising the compounds present in the flow (), except for most of the water and all the acetic acid, removed in the flow () from the bottom of (C).

Method for purifying acrylic acid obtained by oxidation of propylene and/or acrolein

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&deg; C. and 380&deg; C.; a crystallisation temperature less than 35&deg; C. and a viscosity less than 10 mPa&middot;s in a range of temperature between 30-80&deg; C.

Purification of acrylic acid obtained by catalytic oxidation of propylene

Acrylic acid obtained by catalytic oxidation of propylene, extracted by countercurrent washing of the reaction gases which at least one hydrophobic heavy solvent in an extraction column (C1) is purified. To this end, a distillation of the stream (5) obtained at the bottom of the column (C1) is conducted in a column (C3) so as to obtain a very pure acrylic acid stream (6) at the top of the column (C3), allowing acrylic acid to pass at the bottom (7); the bottom stream (7) is conveyed as feed into the lower part of a distillation column (C4) from which a stream (9) rich in maleic anhydride and impurities of boiling temperatures situated between that of acrylic acid and that of the heavy solvent is drawn off sideways on a tray situated between the feed and the top of the column; a stream (8) rich in acrylic acid, which is returned as feed to the column (C3) is distilled at the top of the column (C4); and a stream (1) containing heavy solvent and heavy impurities, which is recycled to the top of the column (C1), is recovered at the bottom of the column (C4).

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Saint-Avold, France

Denis Laurent