Abstract: A process for producing alkyl methacrylates, in particular methyl methacrylate (MMA), includes production of methacrolein (MAL) in a first reaction stage; direct oxidative esterification (DOE) of the methacrolein with an alcohol, preferably methanol, to afford an alkyl methacrylate in a second reaction stage; and workup of the alkyl methacrylate crude product from the second reaction stage. An optimized workup of the reactor output from the oxidative esterification of methacrolein involves minimizing the amount of employed water, the amount of employed acid, and/or the amount of aqueous waste streams, through an optimized recycling of the generated process water streams.

Abstract: A novel process can be used for a heterogeneously catalysed oxidation reaction, in the presence of a pulverulent noble metal-containing catalyst, where (meth)acrolein, an alkyl alcohol, in particular methanol, and an oxygen-containing gas are converted to an alkyl (meth)acrylate, in particular methyl (meth)acrylate. A corresponding reactor suitable for performing the reaction is also useful. The process allows for an effective retention of the particulate catalyst and the continuous discharge of fines fractions of the catalyst powder which are present, particularly in a fresh catalyst batch as a consequence of its preparation. Such fines fractions may also be produced by abrasion during the reaction. The process allows for effective recycling, recovery, and utilization of these discharged catalyst fractions.

Abstract: A process can be used for producing optical molding materials on the basis of methyl methacrylate (MMA). The MMA produced by an optimized method and the molding materials feature in particular a very low yellowness index. This MMA has been produced by direct oxidative esterification of methacrolein. An optimized workup of the reactor output from the oxidative esterification of methacrolein can be used for removing particularly discoloring byproducts. This process moreover has the advantage that fewer demands are placed on plant apparatus configuration.

Abstract: A novel process can be used for purifying methyl methacrylate (MMA) contaminated with low-boiling components by distillation, where the process involves producing MMA by oxidative esterification, and a crude product containing methyl propionate (MP), methyl isobutyrate (MIB), and methacrolein (MAL) as low-boiling components. The process is compatible with MMA produced from C2-based methacrolein containing the low-boiling components specified.

Abstract: A process can be used for producing hydroxyalkyl (meth)acrylate esters, in particular hydroxyethyl methacrylate (HEMA). The process involves a first reaction of (meth)acrolein with at least one polyhydric alcohol, in particular ethylene glycol, in the presence of a first catalyst C1, wherein a first reaction product containing a cyclic acetal is obtained. The process then involves a second reaction of the first reaction product with oxygen in the presence of a second catalyst C2, wherein a second reaction product containing at least one hydroxyalkyl (meth)acrylate ester is obtained. After the first reaction, water and optionally further components, in particular (meth)acrolein and/or the polyhydric alcohol, e.g. ethylene glycol, are at least partially removed from the first reaction product.

Abstract: A process produces methyl methacrylate by direct oxidative esterification of methacrolein. Methyl methacrylate is used in large amounts for producing polymers and copolymers with other polymerizable compounds. An optimized workup of the reactor discharge from the oxidative esterification of methacrolein allows for co-discharged fine catalyst particles to be very efficiently separated and optionally removed or recycled. In addition, this process can reduce the formation of byproducts in extended continuous operation compared to known variant. A reactor system contains stirrer configurations which allow virtually abrasion-free operation and thus a catalyst on-stream time of several years.

Abstract: A process for producing alkyl methacrylates, in particular methyl methacrylate (MMA), includes production of methacrolein (MAL) in a first reaction stage; direct oxidative esterification (DOE) of the methacrolein with an alcohol, preferably methanol, to afford an alkyl methacrylate in a second reaction stage: and workup of the alkyl methacrylate crude product from the second reaction stage. An optimized workup of the reactor output from the oxidative esterification of methacrolein involves minimizing the amount of employed water, the amount of employed acid, and/or the amount of aqueous waste streams, through an optimized recycling of the generated process water streams.

Abstract: A process for producing alkyl methacrylates, in particular methyl methacrylate (MMA), includes production of methacrolein (MAL) in a first reaction stage; direct oxidative esterification (DOE) of the methacrolein with an alcohol, preferably methanol, to afford an alkyl methacrylate in a second reaction stage; and workup of the alkyl methacrylate crude product from the second reaction stage. An optimized workup of the reactor output from the oxidative esterification of methacrolein involves minimizing the amount of employed water, the amount of employed acid, and/or the amount of aqueous waste streams, through an optimized recycling of the generated process water streams.

Abstract: A novel process can be used for purifying methyl methacrylate (MMA) contaminated with low-boiling components by distillation, where the process involves producing MMA by oxidative esterification, and a crude product containing methyl propionate (MP), methyl isobutyrate (MIB), and methacrolein (MAL) as low-boiling components. The process is compatible with MMA produced from C2-based methacrolein containing the low-boiling components specified.

Abstract: A novel process can be used for a heterogeneously catalysed oxidation reaction, in the presence of a pulverulent noble metal-containing catalyst, where (meth)acrolein, an alkyl alcohol, in particular methanol, and an oxygen-containing gas are converted to an alkyl (meth)acrylate, in particular methyl (meth)acrylate. A corresponding reactor suitable for performing the reaction is also useful. The process allows for an effective retention of the particulate catalyst and the continuous discharge of fines fractions of the catalyst powder which are present, particularly in a fresh catalyst batch as a consequence of its preparation. Such fines fractions may also be produced by abrasion during the reaction. The process allows for effective recycling, recovery, and utilization of these discharged catalyst fractions.

Abstract: A process produces methyl methacrylate by direct oxidative esterification of methacrolein. Methyl methacrylate is used in large amounts for producing polymers and copolymers with other polymerizable compounds. An optimized workup of the reactor discharge from the oxidative esterification of methacrolein allows for co-discharged fine catalyst particles to be very efficiently separated and optionally removed or recycled. In addition, this process can reduce the formation of byproducts in extended continuous operation compared to known variant. A reactor system contains stirrer configurations which allow virtually abrasion-free operation and thus a catalyst on-stream time of several years.

Abstract: A process can be used for producing optical molding materials on the basis of methyl methacrylate (MMA). The MMA produced by an optimized method and the molding materials feature in particular a very low yellowness index. This MMA has been produced by direct oxidative esterification of methacrolein. An optimized workup of the reactor output from the oxidative esterification of methacrolein can be used for removing particularly discoloring byproducts. This process moreover has the advantage that fewer demands are placed on plant apparatus configuration.

Abstract: A process for producing alkyl methacrylates, in particular methyl methacrylate (MMA), includes production of methacrolein (MAL) in a first reaction stage; direct oxidative esterification (DOE) of the methacrolein with an alcohol, preferably methanol, to afford an alkyl methacrylate in a second reaction stage; and workup of the alkyl methacrylate crude product from the second reaction stage. An optimized workup of the reactor output from the oxidative esterification of methacrolein involves minimizing the amount of employed water, the amount of employed acid, and/or the amount of aqueous waste streams, through an optimized recycling of the generated process water streams.

Abstract: A process is useful for producing optical molding materials on the basis of methyl methacrylate (MMA), wherein this MMA has been produced by an optimized method and the molding materials feature in particular a very low yellowness index. This MMA has been produced by direct oxidative esterification of methacrolein. In particular, an optimized workup of the reactor output from the oxidative esterification of methacrolein is useful for removing particularly discoloring byproducts. This process moreover has the advantage that fewer demands than described in related art are placed on plant apparatus configuration.

Abstract: A process for preparing methyl methacrylate by direct oxidative esterification of methacrolein has elevated yields compared to known processes. Methyl methacrylate (MMA) 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 produced by transesterification with the appropriate alcohol. There is consequently a great interest in very simple, economic, and environmentally friendly processes for preparing methyl methacrylate. A superior workup of the reactor output from the oxidative esterification of methacrolein allows specific by-products to be isolated and then additionally converted to alkyl methacrylates, especially to MMA.

Abstract: The present invention relates to a novel process for performing a heterogeneously catalyzed reaction for oxidative esterification of aldehydes to give carboxylic esters. Against this background, it has been possible by the present process according to the invention to perform such processes for longer periods without disruption, with constant or even increased activities and selectivities. This gives rise to the possibility of performing such processes in a very simple, economically viable and environmentally benign manner.

Abstract: A process for preparing methyl methacrylate by direct oxidative esterification of methacrolein has elevated yields compared to known processes. Methyl methacrylate (MMA) 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 produced by transesterification with the appropriate alcohol. There is consequently a great interest in very simple, economic, and environmentally friendly processes for preparing methyl methacrylate. A superior workup of the reactor output from the oxidative esterification of methacrolein allows specific by-products to be isolated and then additionally converted to alkyl methacrylates, especially to MMA.

Abstract: The present invention relates to a novel process for performing a heterogeneously catalyzed reaction for oxidative esterification of aldehydes to give carboxylic esters. Against this background, it has been possible by the present process according to the invention to perform such processes for longer periods without disruption, with constant or even increased activities and selectivities. This gives rise to the possibility of performing such processes in a very simple, economically viable and environmentally benign manner.

Abstract: A process is useful for producing optical molding materials on the basis of methyl methacrylate (MMA), wherein this MMA has been produced by an optimized method and the molding materials feature in particular a very low yellowness index. This MMA has been produced by direct oxidative esterification of methacrolein. In particular, an optimized workup of the reactor output from the oxidative esterification of methacrolein is useful for removing particularly discoloring byproducts. This process moreover has the advantage that fewer demands than described in related art are placed on plant apparatus configuration.

Abstract: The present invention relates to a process for preparing alpha-hydroxycarboxylic esters proceeding from hydrogen cyanide, wherein the ammonia formed in the step of alcoholysis of the corresponding alpha-hydroxycarboxamide is recycled into a hydrogen cyanide preparation process after a purification step.