Abstract: The present invention relates to novel catalysts for oxidative esterification, by means of which, for example, (meth)acrolein can be converted to methyl (meth)acrylate. The catalysts of the invention are especially notable for high mechanical and chemical stability even over very long periods. This especially relates to an improvement in the catalyst service life, activity and selectivity over prior art catalysts which lose activity and/or selectivity relatively quickly in continuous operation in media having even a small water content.

Abstract: The present invention relates to a process for producing methyl methacrylate, comprising the following steps: A) producing methacrolein and B) reacting the methacrolein obtained in step A) in an oxidative esterification reaction to give methyl methacrylate, characterized in that the two steps A) and B) take place in a liquid phase at a pressure of from 2 to 100 bar, and step B) is carried out in the presence of a heterogeneous noble-metal-containing catalyst comprising metals and/or comprising metal oxides.

Abstract: A process for performing a heterogeneously catalysed reaction in a three-phase reactor, where there is at least one liquid phase, at least one gaseous phase and at least one solid phase in the reactor and the reactor has at least two zones, with the reaction mixture being conveyed downward in zone 1, the reaction mixture being conveyed upward in zone 2, zones 1 and 2 being separated from one another by a dividing wall, and in that the ratio between the average catalyst concentrations in zone 2 and in zone 1 is greater than 2.

Abstract: The present invention relates to a process for preparing alkyl methacrylates, especially MMA, and methacrylic acid, based on methacrolein, which has been oxidatively esterified in a second process stage. Methacrolein is obtainable in principle from C2 and C4 units. The present process has the advantage that the alkyl methacrylate and methacrylic acid can be obtained in a simple manner, in high yields and high purities, either as a mixture or as isolated product streams. In particular, the process of the invention has the great advantage that especially the ratio of the desired methacrylic acid and alkyl methacrylate, especially MMA, products can be adjusted freely within a wide range and varied by chemical engineering measures and operating parameters.

Abstract: The present invention relates to a process for producing methyl methacrylate, comprising the following steps: A) producing methacrolein and B) reacting the methacrolein obtained in step A) in an oxidative esterification reaction to give methyl methacrylate, characterized in that the two steps A) and B) take place in a liquid phase at a pressure of from 2 to 100 bar, and step B) is carried out in the presence of a heterogeneous noble-metal-containing catalyst comprising metals and/or comprising metal oxides.

Abstract: The present invention relates to a process for preparing methyl methacrylate by direct oxidative esterification of methacrolein. Methyl methacrylate is used in large amounts for preparing polymers and copolymers with other polymerizable compounds. In addition, methyl methacrylate is an important synthesis unit for a variety of specialty esters based on methacrylic acid (MAA) which can be prepared by transesterification with the appropriate alcohol. There is consequently a great interest in very simple, economic and environmentally friendly processes for preparing this starting material. In particular the present invention relates to an optimized workup of the reactor effluent from the oxidative esterification of methacrolein by means of which process waste streams can be minimized and process water can be recycled in optimal fashion. The methacrylic acid generated in the process is also optimally recovered and isolated or converted into the commodity alkyl methacrylate.

Abstract: The present invention relates to a process for producing methyl methacrylate, comprising the following steps: A) producing methacrolein and B) reacting the methacrolein obtained in step A) in an oxidative esterification reaction to give methyl methacrylate, characterized in that the two steps A) and B) take place in a liquid phase at a pressure of from 2 to 100 bar, and step B) is carried out in the presence of a heterogeneous noble-metal-containing catalyst comprising metals and/or comprising metal oxides.

Abstract: Catalysts for oxidative esterification can be used, for example, for converting (meth)acrolein to methyl (meth)acrylate. The catalysts are especially notable for high mechanical and chemical stability even over very long time periods, including activity and/or selectivity relatively in continuous operation in media having even a small water content.

Abstract: The present invention describes a process for dehydrating alpha-substituted carboxylic acids in the presence of water at high pressures while avoiding by-products.

Abstract: The present invention relates to a catalytic continuous process for producing methyl methacrylate, said process comprising the step of reacting methacrolein with oxygen and methanol in the presence of a heterogeneous noble-metal-containing catalyst in an oxidative esterification reaction to give methyl methacrylate, characterized in that the stationary concentration of the starting material methacrolein is equal to or less than 12% by weight based on the total weight of the reaction mixture in the reactor, and the ratio F between the total liquid volume within the reactor expressed in liters divided by the total weight of catalyst in the reactor expressed in kilograms is equal to or less than 4.

Abstract: The present invention relates to a process for producing methyl methacrylate, comprising the following steps: A) producing methacrolein and B) reacting the methacrolein obtained in step A) in an oxidative esterification reaction to give methyl methacrylate, characterized in that the two steps A) and B) take place in a liquid phase at a pressure of from 2 to 100 bar, and step B) is carried out in the presence of a heterogeneous noble-metal-containing catalyst comprising metals and/or comprising metal oxides.

Abstract: The present invention relates to a process for producing methyl methacrylate, comprising the following steps: A) producing methacrolein and B) reacting the methacrolein obtained in step A) in an oxidative esterification reaction to give methyl methacrylate, characterized in that the two steps A) and B) take place in a liquid phase at a pressure of from 2 to 100 bar, and step B) is carried out in the presence of a heterogeneous noble-metal-containing catalyst comprising metals and/or comprising metal oxides.

Abstract: The present invention relates to a process for preparing alpha-hydroxycarboxylic esters from the alcoholysis of alpha-hydroxycarboxamides in the gas phase, characterized in that the conversion is effected in the presence of water.

Abstract: The present invention relates to a process for preparing methyl methacrylate by a direct oxidative esterification of methacrolein with oxygen and methanol, which is conducted in the liquid phase at a pressure of 2 to 100 bar with a gold catalyst. According to the invention, the liquid phase is withdrawn continuously from the reactor and optionally enriched with oxygenous gas, the pH, after the withdrawal, is adjusted to a pH between 5 and 9 by means of addition of a basic solution and this liquid phase is conducted back into the reactor again to an extent of at least 50%.

Abstract: The present invention relates to a process for preparing methyl methacrylate by direct oxidative esterification of methacrolein and the preparation of methacrolein. It is a feature of this novel process that it was possible to distinctly increase the yield and the efficiency of the process compared to the prior art through a sequence of different distillation steps.

Abstract: The present invention relates to a process for hydrolysis of acetone cyanohydrin (ACH) by means of sulphuric acid within the ACH sulpho process for preparation of methacrylic acid (MAA) or methyl methacrylate (MMA).

Abstract: The present invention relates to an apparatus for metering flowable media or gases, and to the use thereof.

Abstract: The present invention relates to a process for hydrolysis of acetone cyanohydrin (ACH) by means of sulphuric acid within the ACH sulpho process for preparation of methacrylic acid (MAA) or methyl methacrylate (MMA).

Abstract: The present invention relates to an apparatus for metering flowable media or gases, and to the use thereof.

Abstract: The invention relates to a process for preparing ETBE from technical mixtures which comprise at least 1-butene, isobutene, n-butane and 2-butenes, by reacting the isobutene present, distillatively removing a fraction comprising 1-butene and isobutene and again reacting the isobutene present therein to give ETBE.