Abstract: The present invention relates to a process for preparing carboxamides by amidating nitriles in the presence of sulphuric acid, wherein the reaction is performed in a Taylor reactor. The process enables a simple and inexpensive preparation of these compounds. The present invention further provides processes for preparing (meth)acrylamides and alkyl(meth)acrylates, which comprise an inventive amidation reaction.

Abstract: The invention relates to a process for preparing acetone cyanohydrin and to a process for preparing alkyl methacrylates, in which an acetone cyanohydrin as can be prepared in accordance with the present invention is used.

Abstract: The subject-matter of the present invention relates in principle to a process for preparing alkyl esters of methacrylic acid and its conversion products, which can be used in a multitude of chemical synthesis processes which can lead to a wide variety of different further processing products, and to an apparatus for performing this process.

Abstract: The present invention relates in general terms to a process for preparing acetone cyanohydrin, comprising as steps: A. contacting acetone and hydrocyanic acid in a reactor to give a reaction mixture, the reaction mixture being circulated, to obtain acetone cyanohydrin; B. cooling at least some of the reaction mixture; C. discharging at least a portion of the acetone cyanohydrin obtained from the reactor; D. continuously distilling the discharged acetone cyanohydrin obtained to obtain an acetone cyanohydrin bottom product and an acetone top product in a distillation column; E. recycling at least a portion of the acetone top product into step A, the acetone top product being kept at less than 60° C.

Abstract: The present invention relates to a process for preparing alkyl methacrylates and their conversion products which can be used in a multitude of chemical synthesis processes which can lead to a wide variety of different further processing products, and to an apparatus for performing this process.

Abstract: The present invention relates in general terms to a process for preparing alkyl methacrylates, comprising as steps: providing an acetone cyanohydrin by a process according to one of the preceding claims; contacting the acetone cyanohydrin with an inorganic acid to obtain a methacrylamide; contacting the methacrylamide with an alcohol in the presence of an inorganic acid in a reactor to obtain an alkyl methacrylate; continuously discharging at least a portion of the alkyl methacrylate from the reactor into a distillation column as a vapour stream; the discharge being effected by feeding a discharge stream comprising steam into the reactor, to an apparatus for preparing alkyl methacrylates, to a process for preparing polymers based at least partly on alkyl methacrylates, to the use of the alkyl methacrylates obtainable by the process according to the invention in chemical products, and to chemical products based on alkyl methacrylates obtainable by the process according to the invention.

Abstract: The invention relates in general terms to a process for preparing to a process for purifying an alkyl methacrylate, comprising the steps of: A. providing an alkyl methacrylate with an impurity: B. adsorbing at least some of the impurity onto a purifying solid to obtain an ultrapure alkyl methacrylate, to a process for preparing an ultrapure alkyl methacrylate, to an apparatus for preparing alkyl methacrylates, to a process for preparing a polymer based at least partly on alkyl methacrylates, to the use of an alkyl methacrylate obtained according to the invention in chemical products, and to chemical products comprising an alkyl methacrylate obtained according to the invention.

Abstract: The present invention relates in general terms to a process for preparing acetone cyanohydrin, comprising as steps: A. contacting acetone and hydrocyanic acid in a reactor to give a reaction mixture, the reaction mixture being circulated, to obtain acetone cyanohydrin; B. cooling at least some of the reaction mixture by flowing it through a cooling region of a cooler, the cooler including one cooling element or at least two cooling elements; C.

Abstract: Continuous process for preparing alpha-hydroxycarboxylic esters, in which the reactants reacted are alpha-hydroxycarboxamide with an alcohol in the presence of a catalyst to obtain a product mixture which comprises alpha-hydroxycarboxylic ester, ammonia, unconverted alpha-hydroxycarboxamide and alcohol, and catalyst; wherein a?) reactant streams comprising, as reactants, an alpha-hydroxycarboxamide, an alcohol and a catalyst are fed into a pressure reactor; b?) the reactant streams are reacted with one another in the pressure reactor at a pressure in the range of 1 bar to 100 bar; c?) the product mixture which results from step b) and comprises alpha-hydroxycarboxylic ester, unconverted alpha-hydroxycarboxamide and catalyst, and also ammonia and alcohol, is discharged from the pressure reactor; and d?) the product mixture is depleted in alcohol and ammonia by distilling off ammonia at a pressure which is constantly kept greater than 1 bar without the aid of additional stripping media.

Abstract: The invention relates to a process for the selective, economically viable preparation of methacrylic acid and methacrylic esters starting from acetone cyanohydrin, wherein, in a first step, 2-hydroxy-2-methylpropionic acid is prepared by reacting acetone cyanohydrin with sulphuric acid in the presence of water and a suitable polar solvent and is isolated and methacrylic acid is subsequently prepared by ?-elimination of water starting from 2-hydroxy-2-methylpropionic acid.

Abstract: The present invention relates to processes for transesterification, comprising the steps of A) mixing an organic acid a) with an ester b) and B) transferring the alcohol radical of the ester b) to the acid a) to obtain the ester of the acid a) and the acid of the ester b), step B) being carried out in a still

Abstract: The present invention relates to processes for preparing alkyl (meth)acrylates, comprising the steps of transesterifying an alkyl ?-hydroxycarboxylate with (meth)acrylic acid to obtain alkyl (meth)acrylates and ?-hydroxycarboxylic acid, and dehydrating the ?-hydroxycarboxylic acid to obtain (meth)acrylic acid.

Abstract: The invention relates to a process for the selective, economically viable preparation of methacrylic acid and methacrylic esters starting from acetone cyanohydrin, wherein, in a first step, 2-hydroxy-2-methylpropionic acid is prepared by reacting acetone cyanohydrin with sulphuric acid in the presence of water and a suitable polar solvent and is isolated and methacrylic acid is subsequently prepared by ?-elimination of water starting from 2-hydroxy-2-methylpropionic acid.

Abstract: The invention relates to a process for continuous preparation of alkyl (meth)acrylates by transesterification of methyl (meth)acrylate using alcohols which are high-boiling relative to methanol. A particular workup technique achieves product qualities which have hitherto not been attained. Very high space-time and overall yields can also be achieved.

Abstract: The invention relates to a process for continuous preparation of alkyl (meth)acrylates by transesterification of methyl (meth)acrylate using alcohols which are high-boiling relative to methanol. A particular workup technique achieves product qualities which have hitherto not been attained. Very high space-time and overall yields can also be achieved.

Abstract: The present invention relates to a process of recovering monomeric esters of substituted or unsubstituted acrylic acid from polymer material having corresponding structural units by depolymerization by means of a fine-grained heat-transfer medium which is maintained above the depolymerization temperature of the polymer material. In a reactor, the polymer material is brought in contact with hot, mechanically fluidized heat-transfer medium. The resulting vapors are withdrawn and condensed, where the hot heat-transfer medium is continuously supplied at one end of the reactor, and cooled heat-transfer medium is discharged at the other end.

Abstract: The subject invention relates to method for processing crude polyoxymethylene in which the isolation of unstable components from crude polyoxymethylene, such as residual monomers which are at least partly in the form of cyclic formaldehyde derivatives, is effected by treatment of the crude polyoxymethylene with an inert gaseous medium. The method of the invention is characterized in that the gaseous medium contains at least 10 volume % of water vapor, and less than 0.1 volume % of a volatile base, and/or less than 1 volume % of a volatile solvent. In an alternative variant method, the gaseous medium contains at least 10 volume % of water vapor and the treatment occurs at a temperature between 114.degree. C and the softening temperature of the crude polyoxymethylene and at a pressure of less 1.2 .multidot.10.sup.5 Pa.