Abstract: A process for preparing acrylic acid, in which heterogeneously catalyzed gas phase partial oxidation of at least one C3 precursor of acrylic acid with molecular oxygen over catalysts in the solid state of matter at elevated temperature affords a product gas mixture comprising acrylic acid, water vapor and secondary components, then the product gas mixture is directed into a condensation column equipped with separating internals, the product gas mixture is allowed to ascend into itself within the condensation column and undergoes fractional condensation, separating the product gas mixture into a bottoms liquid comprising conversion products and secondary components that are higher-boiling than acrylic acid, a crude acrylic acid comprising water and secondary components that have been depleted overall as target product, an acid water still comprising acrylic acid and secondary components, and a residual gas mixture comprising secondary components that are lower-boiling than water, the target product is conducte

Abstract: The present invention relates to a process for the continuous preparation of (meth)acrylate by reacting an alcohol with a (meth)acrylic acid using at least one control unit which is closed-loop controlled by a sensor (S).

Abstract: The present invention relates to a method for transporting a liquid F by means of a pump P, wherein the liquid F comprises at least 10% by weight of a (meth)acrylic monomer, the pump P has a pump space (3), the pump space (3) comprises at least one transport element (4) for transporting the liquid F, the transport element (4) is connected to a drive shaft (6) in such a way that the drive shaft (6) can transmit a torque to the transport element (4), the mounting of the drive shaft is effected by means of at least two sliding bearings (5) in the pump space (3) and the sliding bearings (5) are composed of tungsten carbide.

Abstract: The present invention relates to a method of redissociating Michael adducts of acrylic acid present in a liquid F in a redissociation apparatus comprising at least one separating column K, an evaporator V and a pump P, wherein, in the event of an unwanted rise in the viscosity of the residue R in the bottom space of the separating column K, the feed of the liquid F into the redissociation apparatus is stopped, the residue R in the bottom space of the separating column K is diluted and cooled with a solvent 1, and the bottom space of the separating column K is emptied.

Abstract: Process for making a powder or granule containing (A) at least one chelating agent selected from alkali metal salts of methyl glycine diacetic acid (MGDA) and of iminodisuccinic acid (IDS), (B) at least one compound of general formula (I a) or (I b) wherein A1 is selected from (CH2)a wherein the variable a is in the range of from 4 to 20, e is selected from zero and 1, and R1 being the same or different and selected from O—C1-C10-alkyl and C1-C10-alkyl, and, optionally, (C) at least one homo- or copolymer of (meth)acrylic acid, partially or fully neutralized with alkali, said process comprising the steps of (a) providing an aqueous solution or slurry containing chelating agent (A) and said compound (B) and, if applicable, (co)polymer (C), with a pH value in the range of from 10 to 12, (b) removing most of said water by spray drying or spray granulation.

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.