Abstract: The present invention relates to a process for the preparation of methacrylic acid or methacrylic esters, comprising the process steps of IA) preparation of 3-hydroxyisobutyric acid by a process comprising the process step of bringing a cell which has been genetically modified in comparison with its wild type in such a way that it is capable of forming more 3-hydroxyisobutyric acid, or polyhydroxyalkanoates based on 3-hydroxyisobutyric acid in comparison with its wild type, into contact with a nutrient medium comprising, as carbon source, carbohydrates, glycerol, carbon dioxide, methanol, L-valine or L-glutamate under conditions under which 3-hydroxyisobutyric acid or polyhydroxyalkanoates based on 3-hydroxyisobutyric acid are formed from the carbon source, if appropriate, isolation of the 3-hydroxyisobutyric acid from the nutrient medium and also, if appropriate, neutralization of the 3-hydroxyisobutyric acid, IB) dehydration of the 3-hydroxyisobutyric acid with formation of methacrylic acid and also, where

Abstract: The invention relates to a method for the continuous production of unsaturated carboxylic acid anhydrides of general formula (I): R—C(O)—O—C(O)—R (I), wherein R is an unsaturated organic group with 2 to 12 C atoms, by reaction of a ketene with an unsaturated carboxylic acid of general formula (II): R—COOH (II), wherein R is defined as above, in an apparatus which has a reaction zone (1) for the reaction of a ketene with an unsaturated carboxylic acid of general formula (II), and a reaction zone (2) for the subsequent reaction of the crude anhydride mixture and a rectification column with an upper, a middle and a lower zone, in the sump of which an inert boiling oil is present.

Abstract: The present invention relates to a process for preparing hydrogen cyanide by the Andrussow process by reacting methane-containing gas, ammonia and oxygen-containing gas over a catalyst at elevated temperature, wherein the proportion by volume of oxygen in relation to the total volume of nitrogen and oxygen (O2/(O2+N2)) is in the range of 0.2 to 1.0 and the reaction is performed with a non-ignitable reactant gas mixture.

Abstract: The present invention relates to a cell which has been modified in comparison with its wild type in such a way that it is capable of forming more, by comparison with its wild, 3-hydroxyisobutyric acid or poly-hydroxyalkanoates based on 3-hydroxyisobutyric acid via methylmalonate-semialdehyde or 3-hydroxybutyryl-coenzyme A as precursors. The invention also relates to a method of generating a genetically modified cell, to the genetically modified cell obtainable by these methods, to a method of producing 3-hydroxyisobutyric acid or polyhydroxyalkanoates based on 3-hydroxyisobutyric acid, to a method of producing methacrylic acid or methacrylic esters, and to a method of producing polymethacrylic acid or polymethacrylic esters. The present invention furthermore relates to an isolated DNA, to a vector, to the use of this vector for transforming a cell, to a transformed cell, and to a polypeptide.

Abstract: The present invention relates to a process for preparing (meth)acrylic acid, characterized in that a cyclic ester is converted to (meth)acrylic acid in the presence of a catalyst. The (meth)acrylic acid prepared can in particular be converted to (meth)acrylates.

Abstract: The present invention relates to a process for preparing alkyl(meth)acrylates, characterized in that the process has a step in which a cyanohydrin is hydrolysed with an enzyme whose residual activity after the conversion of methacrylonitrile in the presence of 20 mM cyanide ions at 20° C. after 30 min is at least 90% of the residual activity of the enzyme which has been used under otherwise identical conditions in the absence of cyanide ions.

Abstract: The present invention relates to a process for preparing tetramethylglycolide by heating a composition which comprises at least 50% by weight of 2-hydroxy-isobutyric acid and/or tetramethylglycolide to a temperature of at least 100° C.

Abstract: Process for continuously preparing unsaturated carboxylic anhydrides of the general formula I R—C(O)—O—C(O)—R??(I) in which R is an unsaturated organic radical having 2 to 12 carbon atoms by transanhydridization of an aliphatic carboxylic anhydride with a carboxylic acid of the general formula II R—COOH??(II) in which R is as defined above in a rectification column having an upper, middle and lower region, characterized in that f) an inert boiling oil is initially charged in the bottom of the column, g) the reactants are fed into a reaction region in stoichiometric ratios, h) the carboxylic acid formed as the by-product is withdrawn at the top of the column, i) the unconverted reactants are recycled into the reaction region and j) the product of the formula I is obtained via a side draw, preferably between the middle and lower column region.

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: 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 reactant streams comprising, as reactants, an alpha-hydroxycarboxamide, an alcohol and a catalyst are fed into a pressure reactor; the reactant streams are reacted with one another in the pressure reactor at a pressure in the range of 1 bar to 100 bar; and 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. The continuous process can be employed particularly advantageously on the industrial scale.

Abstract: Process for distillatively purifying polymerizable compounds using a high-boiling, inert, thermally long-term-stable substance as a boiling oil, characterized in that the boiling oil is disposed in the bottom of a rectification column.

Abstract: The invention relates to a method for the continuous production of unsaturated carboxylic acid anhydrides of general formula (I): R—C(O)—O—C(O)—R (I), wherein R is an unsaturated organic group with 2 to 12 C atoms, by reaction of a ketene with an unsaturated carboxylic acid of general formula (II): R—COOH (II), wherein R is defined as above, in an apparatus which has a reaction zone (1) for the reaction of a ketene with an unsaturated carboxylic acid of general formula (II), and a reaction zone (2) for the subsequent reaction of the crude anhydride mixture and a rectification column with an upper, a middle and a lower zone, in the sump of which an inert boiling oil is present.

Abstract: The invention relates to an apparatus and a process for carrying out equilibrium reactions continuously.

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 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 invention relates to an improved method for the continuous production of alkyl(methyl)acrylates by transesterification of methyl(meth)acrylate with alcohols that are heavy in comparison with methanol. A special processing technique makes it possible to obtain new levels of product quality. Very high space-time-overall yields can also be obtained. The invention is characterized by the multiple use of a homogeneous catalyst which thereby reduces the costs of auxiliary agents significantly.

Abstract: A process for the production of hydrogen cyanide is provided, wherein hydrogen cyanide is synthesized by reacting methane or methane-containing natural gas, ammonia and oxygen-enriched air or oxygen in the presence of a catalyst comprising platinum or a platinum alloy; wherein the reactants are present in the following molar ratios [ O 2 ] [ O 2 + N 2 ] = 0.25 ? ? to ? ? 1.0 ; [ CH 4 ] [ NH 3 ] = 0.95 ? ? to ? ? 1.05 ; and where a molar ratio of ammonia to the sum of oxygen and nitrogen obeys the following relationship: Y=m·X?a, wherein Y = [ NH 3 ] [ O 2 + N 2 ] X = [ O 2 ] [ O 2 + N 2 ] m=1.25 to 1.40; and a=0.05 to 0.14.

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: A process for the production of hydrogen cyanide is provided, wherein hydrogen cyanide is synthesized by reacting methane or methane-containing natural gas, ammonia and oxygen-enriched air or oxygen in the presence of a catalyst comprising platinum or a platinum alloy; wherein the reactants are present in the following molar ratios 1 [ O 2 ] [ O 2 + N 2 ] = 0.25 ⁢   ⁢ to ⁢   ⁢ 1.0 ; [ CH 4 ] [ NH 3 ] = 0.95 ⁢   ⁢ to ⁢   ⁢ 1.