Abstract: Process for inhibiting the undesired free-radical polymerization of acrylic acid present in a liquid phase P, wherein the acrylic acid content of P is at least 10% by weight, the liquid phase P comprises in the range from 25 to 1000 ppmw of glyoxal based on the weight of the acrylic acid present in P and the liquid phase P is admixed with protoanemonine in an amount that results in a protoanemonine content in the range from 0.5 to 100 ppmw based on the weight of the acrylic acid present in P, and a liquid phase P, wherein the acrylic acid content of P is at least 10% by weight and the liquid phase P comprises in the range from 25 to 1000 ppmw of glyoxal and in the range from 0.5 to 100 ppmw of protoanemonine, in each case based on the weight of the acrylic acid present in P.

Abstract: Process for inhibiting the undesired free-radical polymerization of acrylic acid present in a liquid phase P, wherein the acrylic acid content of P is at least 10% by weight, the liquid phase P comprises in the range from 25 to 1000 ppmw of glyoxal based on the weight of the acrylic acid present in P and the liquid phase P is admixed with furfural in an amount that results in a furfural content in the range from 25 to 1000 ppmw based on the weight of the acrylic acid present in P. Liquid phase P, wherein the acrylic acid content of P is at least 10% by weight and the liquid phase P comprises in the range from 25 to 1000 ppmw of glyoxal and in the range from 25 to 1000 ppmw of furfural in each case based on the weight of the acrylic acid present in P.

Abstract: Process for inhibiting the undesired free-radical polymerization of acrylic acid present in a liquid phase P, wherein the acrylic acid content of P is at least 10% by weight, the liquid phase P comprises in the range from 25 to 1000 ppmw of glyoxal based on the weight of the acrylic acid present in P and the liquid phase P is admixed with furfural in an amount that results in a furfural content in the range from 25 to 1000 ppmw based on the weight of the acrylic acid present in P. Liquid phase P, wherein the acrylic acid content of P is at least 10% by weight and the liquid phase P comprises in the range from 25 to 1000 ppmw of glyoxal and in the range from 25 to 1000 ppmw of furfural in each case based on the weight of the acrylic acid present in P.

Abstract: A composition for the immediate stopping of a free-radical polymerization comprises a) an inhibitor for the free-radical polymerization selected from among phenothiazines, b) an aprotic solvent and c) an ionic liquid. It serves to stabilize free-radically polymerizable monomers against free-radical polymerization. For the immediate stopping of free-radical polymerizations, the composition is added to a free-radically polymerizing system.

Abstract: A composition for the immediate stopping of a free-radical polymerization comprises a) an inhibitor for the free-radical polymerization selected from among phenothiazines, b) an aprotic solvent and c) an ionic liquid. It serves to stabilize free-radically polymerizable monomers against free-radical polymerization. For the immediate stopping of free-radical polymerizations, the composition is added to a free-radically polymerizing system.

Abstract: A process for production of acrylic acid includes preparing a product gas mixture by a catalytic gas-phase oxidation of a C3 precursor; cooling and contacting the cooled product gas mixture in an absorption column having at least two cooling loops in countercurrent with an absorbent to obtain an absorbate A, containing the absorbent and absorbed acrylic acid; condensing a high boiler fraction of the product gas mixture in a first cooling loop; condensing a low boiler fraction of the product gas mixture in a second cooling loop; maintaining a temperature of the absorbate A in the second cooling loop at a value of at least 56° C.; removing an acid water stream comprising glyoxal from the absorption column at a side take-off located above the second cooling loop; and removing a stream F of absorbate A from the absorption column at a side take-off, located at a height of the absorption column between the first cooling loop and the second cooling loop.

Abstract: Process for manufacturing a coated mesh for oil-water separation by coating a mesh with a curable coating composition and crosslinking the coating thereby providing hydrophilic properties to the surface of the mesh, a coated mesh available by said process and the use of such coated mesh for oil-water separation.

Abstract: The invention is related to a process for production of acrylic acid comprising the following steps: a) preparation of a product gas mixture by a catalytic gas-phase oxidation of at least one C3 precursor compound to acrylic acid, wherein acrylic acid is formed as a main product of the catalytic gas-phase oxidation and glyoxal is formed as a by-product and the product gas mixture comprises acrylic acid and glyoxal, b) cooling of the product gas mixture, c) contacting the product gas mixture in countercourrent with an absorbent, wherein an absorbate A, comprising the absorbent and absorbed acrylic acid, is formed, d) introducing a feed stream F (2) comprising at least part of the absorbate A into a rectification column comprising a rectifying section and a stripping section, e) enriching the absorbent in the stripping section and enriching acrylic acid in the rectifying section, f) withdrawing a stream C of crude acrylic acid comprising at least 90% by weight of acrylic acid out of the rectifying section as a

Abstract: A process for inhibiting unwanted free-radical polymerization of acrylic acid present in a liquid phase P whose acrylic acid content is at least 10% by weight and which, based on the weight of the acrylic acid present therein, additionally comprises at least 100 ppm by weight of propionic acid and at least 100 ppm by weight of glyoxal, in which at least one chemical compound of the element copper is added to the liquid phase P, and the resulting liquid phases P to which a chemical compound of the element copper has been added.

Abstract: In a method of stabilizing acrylic compounds, a liquid phase containing at least one acrylic compound is mixed with at least one metal and at least one ligand. The acrylic compound can be acrylic acid, methacrylic acid, and their respective esters. The metal can be copper, manganese, and cerium. The ligand can be a quinoline compound of formula (I), an N-oxide of a compound of formula (I), 2,2?-bis(2,3-dihydro-3-oxoindolylidene), or an aliphatic y-dentate ligand with y being 2-6 and comprising at least two nitrogen atoms joined by aliphatic or aromatic C1-C4 bridges comprising y-2 further coordinating nitrogen atoms or heteroatoms: where X is OH, NH2, O—(C1-C4)-alkyl, O—C(O)—(C1-C4)-alkyl, or O—C(O)-phenyl; R1 is H, or (C1-C4)-alkyl; R2 is H, (C1-C4)-alkyl, Cl, Br, or SO3H; and R3 is H, Cl or Br.

Abstract: A process for preparing acrylic acid from ethylene oxide and carbon monoxide, in which ethylene oxide is carbonylated in an aprotic solvent with carbon monoxide in the presence of a cobalt catalyst system to give poly-3-hydroxypropionate, the cobalt content in the poly-3-hydroxypropionate formed is reduced with the aid of water and/or an aqueous solution as a precipitation and/or wash liquid, and the poly-3-hydroxypropionate is subsequently split by thermolysis to give acrylic acid.

Abstract: A process for inhibiting unwanted free-radical polymerization of acrylic acid present in a liquid phase P whose acrylic acid content is at least 10% by weight and which, based on the weight of the acrylic acid present therein, additionally comprises at least 100 ppm by weight of propionic acid and at least 100 ppm by weight of glyoxal, in which at least one chemical compound of the element copper is added to the liquid phase P, and the resulting liquid phases P to which a chemical compound of the element copper has been added.

Abstract: In a method of stabilizing acrylic compounds, a liquid phase containing at least one acrylic compound is mixed with at least one metal and at least one ligand. The acrylic compound can be acrylic acid, methacrylic acid, and their respective esters. The metal can be copper, manganese, and cerium. The ligand can be a quinoline compound of formula (I), an N-oxide of a compound of formula (I), 2,2?-bis(2,3-dihydro-3-oxoindolylidene), or an aliphatic y-dentate ligand with y being 2-6 and comprising at least two nitrogen atoms joined by aliphatic or aromatic C1-C4 bridges comprising y-2 further coordinating nitrogen atoms or heteroatoms: where X is OH, NH2, O—(C1-C4)-alkyl, O—C(O)—(C1-C4)-alkyl, or O—C(O)-phenyl; R1 is H, or (C1-C4)-alkyl; R2 is H, (C1-C4)-alkyl, Cl, Br, or SO3H; and R3 is H, Cl or Br.

Abstract: A process for preparing acrylic acid by thermolysis of poly-3-hydroxypropionate in the presence of one or more specific tertiary amines as a catalyst.

Abstract: A process for preparing acrylic acid from ethylene oxide and carbon monoxide, in which ethylene oxide is carbonylated in an aprotic solvent with carbon monoxide in the presence of a cobalt catalyst system to give poly-3-hydroxypropionate, the cobalt content in the poly-3-hydroxypropionate formed is reduced with the aid of water and/or an aqueous solution as a precipitation and/or wash liquid, and the poly-3-hydroxypropionate is subsequently split by thermolysis to give acrylic acid.

Abstract: A process for separating acrylic acid present as a main product and glyoxal present as a by-product in a product gas mixture of a partial gas phase oxidation of a C3 precursor compound, in which a liquid phase P is obtained, which consists of acrylic acid to an extent of at least 70% of its weight and, based on the molar amount of acrylic acid present therein, comprises at least 200 molar ppm of glyoxal, in which the glyoxal is separated from the acrylic acid in the liquid phase P by crystallization.

Abstract: A process for inhibiting unwanted free-radical polymerization of acrylic acid present in a liquid phase P whose acrylic acid content is at least 10% by weight and which, based on the weight of the acrylic acid present therein, additionally comprises at least 100 ppm by weight of propionic acid and at least 100 ppm by weight of glyoxal, in which at least one chemical compound of the element copper is added to the liquid phase P, and the resulting liquid phases P to which a chemical compound of the element copper has been added.

Abstract: A process for removal of a crude acrylic acid from a product gas mixture which comprises glyoxal as a by-product from a heterogeneously catalyzed partial gas phase oxidation of at least one C3 precursor compound, which comprises the absorption of the acrylic acid in a high-boiling absorbent and the rectificative workup of the resulting adsorbate, and in which absorbent present in the bottoms liquid withdrawn from the bottom space of the absorption column is distilled off in a distillation unit and recycled into the absorption, before high boilers which remain are discharged, and in which the glyoxal content of the crude acrylic acid is reduced by restricting the high boiler residence time in the distillation unit.

Abstract: The present invention relates to a process for preparing tertiary alkyl esters of (meth)acrylic acid having at least 4 carbon atoms in the alkyl radical. The process includes reacting (meth)acrylic acid with at least one olefin of formula (I) in homogeneous phase in the presence of an acidic catalyst in a reactor, discharging the resulting reaction mixture from the reactor, separating the discharged reaction mixture into a first mixture which contains the catalyst and a second mixture which contains the tertiary alkyl ester of (meth)acrylic acid having at least 4 carbon atoms in the alkyl radical, and removing the tertiary alkyl ester of (meth)acrylic acid having at least 4 carbon atoms in the alkyl radical from the second mixture in the presence of compound S, which comprises at least one N-oxyl group and is added as a stabilizer.

Abstract: A process for transferring heat to a liquid mixture comprising at least one (meth)acrylic monomer in an indirect heat exchanger, wherein a quaternary ammonium salt, a tertiary amine or a salt thereof with a Brønsted acid is added to the liquid mixture to reduce fouling.