Abstract: The use of amidoximes for stabilisation of ethylenically-unsaturated compounds against undesired radical polymerisation is disclosed. Combinations of amidoximes with phenol and/or phenothiazine compounds have a synergistic effect. Preferred amidoximes are nitrilotris(acetamidoxime) and nitrilotris(propionamidoxime).

Abstract: Thermal separating process between at least one gaseous and at least one liquid stream, of which at least one comprises (meth)acrylic monomers, in a separating column whose separating internals are mass transfer trays, in which the liquid stream is polymerization-inhibited and used for spraying the surface of the separating column, and internal surfaces which are in the shadow region of the spraying are removed from the shadow region by covering.

Abstract: Basic (meth)acrylates IV are prepared by transesterification of alkyl (meth)acrylates I in the presence of a catalyst and working-up of the reaction mixture by distillation, by a process in which a gas or gas mixture which is inert under the reaction conditions is passed through the reaction zone and/or heat exchanger.

Abstract: Higher (meth)acrylates IV are prepared by transesterification of a lower (meth)acrylate I with a higher alcohol R2OH in the presence of a stabilizer or stabilizer mixture and of a catalyst or catalyst mixture, by a process in which the liberated lower alkanol R1OH is separated off and is fed at least partly to the preparation of the lower (meth)acrylate I.

Abstract: This invention relates to a multifunctional operating device (12), especially for mounting into a vehicle, with a rotary switch (16) for selecting functions that can be represented within a display field (40) and on a monitor unit (38). The multifunctional operating device (12) is provided with a combination of the rotary switch (16) and several press switches (18). The press switches (18) are arranged around the rotary switch (16) and are configured and/or arranged in such a way that said press switches are haptically distinguishable. The arrangement of display fields (42) on the monitor unit (38) corresponds at least schematically to the arrangement of the press switches (18), whereby the display fields are allocated to the press switches.

Abstract: The present invention describes a process for preparing (meth)acrylic esters by acid-catalyzed esterification of (meth)acrylic acid or by transesterification of (meth)acrylic esters with alcohols, by adding the (meth)acrylic acid or the (meth)acrylic ester at a metering rate of less than 250 g per hour and liter of reactor volume and/or using at least 0.2 mmol of polymerization inhibitor per kg of alcohol and per meq/kg of peroxid number of the alcohol determined by the Sully method and/or thermally treating the alcohol in the absence of water before the esterification or transesterification.

Abstract: In a thermal separating process between at least one gaseous and at least one liquid stream, of which at least one comprises (meth)acrylic monomers, in a separating column containing sieve trays as separating internals, at least some of the sieve trays are operated above an entrainment fraction of 10% by weight.

Abstract: A process for rectificatively separating fluids comprising (meth)acrylic monomers in a rectification column by directly cooling the vapor comprising (meth)acrylic monomers rising to the top of the rectification column to form top condensate comprising (meth)acrylic monomers, the condensation space at the top of the column being separated from the region of the rectification column containing the separating internals only by at least one chimney tray from which the top condensate formed is removed from the rectification column, which comprises effecting the direct cooling of the vapor in the condensation space in at least two spray zones which are spatially successive and are flowed through by vapor by spraying supercooled top condensate comprising added polymerization inhibitor, and the temperature of the sprayed supercooled top condensate becoming lower from spray zone to spray zone in the flow direction of the vapor.

Abstract: A process for the continuous recovery of (meth)acrylic acid from the reaction gas of a catalytic gas-phase oxidation comprising the following process stages is proposed:

Abstract: Organic compounds are prepared by heterogeneously catalyzed partial gas-phase oxidation of precursor compounds by a process in which a portion of the reaction gas starting mixture is brought from a low initial pressure to a higher final pressure by means of a radial compressor.

Abstract: Noninvasive process for inline and/or online determination of polymer deposited from (meth)acrylic acid and/or (meth)acrylic esters by means of sound velocity measurements, measurements of the absorption coefficients in the infrared, near infrared, ultraviolet and/or visible region of the spectrum of electromagnetic radiation, or Raman spectroscopy, which allows precise control of the process parameters to be carried out during the thermal purification.

Abstract: An inhibitor mixture containing, as components, a) at least one nitroxyl radical (derivative), b) at least one phenol (derivative) and c) at least one chemical compound which contains at least one phosphorus atom which has the oxidation state +3 is preferably used for stabilizing compounds capable of free radical polymerization.

Abstract: A process for preparing acrylic acid and/or acrylates which comprises the following stage A and, if desired, B and C: A: cooling a gaseous reaction mixture which comprises acrylic acid and is obtained in the gas-phase oxidation to prepare acrylic acid, using oligomeric acrylic acid or a mixture of acrylic acid and oligomeric acrylic acid, to give a gaseous mixture comprising acrylic acid and a quench bottom product which comprises oligomeric acrylic acid; B: separating the gaseous mixture comprising acrylic acid, to give a low-boiling fraction, a crude acrylic acid, and a bottom product, which comprises oligomeric acrylic acid; C: esterifying the crude acrylic acid obtained in stage B by means of one or more alkanols.

Abstract: (Meth)acrylic acid is worked up in the presence of at least one stabilizer by a process in which a stabilizer-containing mixture originating from the working-up and substantially freed from (meth)acrylic acid is passed into a distillation apparatus and a stabilizer-containing low boiler stream obtained from said apparatus is recycled to the working-up.

Abstract: A process for working up mixtures containing (meth)acrylic acid and/or (meth)acrylic ester in a column for distilling, rectifying and/or fractionally condensing in the presence of at least one polymerization inhibitor and an oxygen-containing gas, wherein the partial oxygen pressure p(O2) in the gas phase of the entire column is from 2 to 5 hPa.

Abstract: A water lance blower for cleaning heat installations is disclosed. A water lance linked with a water feed conduit system is swivel-mounted with its orifice disposed in a hatch. The water lance can blow a jet of water through the heating installation in operation and through which flames and/or flue gases are guided to wall areas that can be reached from the hatch. The water lance blower is provided with a drive system with at least two drive units that control the water lance, and with a holding device that fastens the water lance blower onto the heating installation. Further, parts of the water feed conduit system are integrated onto the holding device, thereby substantially limiting the size of the water lance blower to the swivel range of the water lance.

Abstract: A process for cleaning apparatus in which (meth)acrylic acid-containing organic solvents have been treated and/or generated and contain fouling and/or polymer and residues of organic solvent, in which the apparatus contents are subjected to a steam distillation in the apparatus.

Abstract: The invention relates to a method for producing (meth)acrylic acid esters by transesterification of the (meth)acrylic acid with an alkanol in the presence of an acid catalyst, a polymerization inhibitor and an organic solvent that forms an azeotropic mixture with water. The reaction mixture is heated to the boiling point of the mixture in a reactor that comprises a distillation unit with a column and a condenser. The azeotropic mixture is distilled off, the organic solvent is returned to the column as reflux and at least a part of the column reflux is contacted with copper or a copper-containing material. The inventive method is advantageous in that substantially no polymerizate is produced in the distillation column.

Abstract: The invention relates to a method for producing (meth)acrylic acid esters by transesterification of the (meth)acrylic acid with a higher alkanol in the presence of an acid catalyst, at least one polymerization inhibitor and one organic solvent that forms an azeotropic mixture with water. The reaction mixture is heated to the boiling point of the mixture in a reactor that comprises a distillation unit with a column and a condenser. The content of the reactor is recirculated via an external evaporator and heated to the boiling point, and the azeotropic mixture is distilled off. The organic solvent forms a reflux and at least a part of the solvent reflux is recirculated between the reactor and the evaporator. The inventive method allows for the production of higher (meth)acrylic acid esters in a reactor with a circulation evaporator without using copper salts as the polymerization inhibitors.

Abstract: Higher (meth)acrylates are prepared by reacting (meth)acrylic acid and the alcohol in the presence of at least one acidic catalyst and at least one polymerization inhibitor and in the presence of a solvent which forms an azeotropic mixture with water and distilling off and condensing the azeotropic mixture, the condensate separating into an aqueous phase and an organic phase, by a process in which