Rohm Gmbh

Roehm Gmbh

Florian Zschunke

Steffen Krill

Belaid Ait Aissa

Daniel Helmut König

Gerhard Kölbl

Andreas Rühling

Rudolf Burghardt

Rüdiger Carloff

Eduard Rundal

Torsten Panak

Alexander Lygin

Marcel Treskow

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.

Process for producing alkyl methacrylates with improved water and acid management

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.

Process for producing optical molding materials

A process and a preparation plant prepares methacrolein from formaldehyde and propionaldehyde, in presence of water and a homogeneous catalyst based at least on an acid and a base. A reaction mixture is introduced into a methacrolein workup plant and separated in a first distillation column, into a first distillation mixture in a gas phase at the top and a second distillation mixture in a liquid phase at the bottom. The first distillation mixture is condensed and, in a first phase separator, the organic phase and the aqueous phase of the condensate are separated from one another. The aqueous phase is introduced into a second distillation column, that is not part of the methacrolein workup plant, and is separated into a third distillation mixture in a gas phase at the top and a fourth distillation mixture at the bottom. The third distillation mixture is introduced into the methacrolein workup plant.

Process for preparing methacrolein from formaldehyde and propionaldehyde and preparation plant for the purpose

A process and a preparation plant can prepare methacrolein from formaldehyde and propionaldehyde in the presence of a homogeneous catalyst mixture based at least on an acid and a base. For a good workup of the reaction mixture leaving the reactor, with a good energy balance and where the process has simplified apparatus implementation, the liquid reaction mixture under pressure is expanded in an expansion vessel and separated into a first expansion mixture in a gas phase and a second expansion mixture in a liquid phase. The first expansion mixture is condensed in a first condenser and the second expansion mixture is introduced into a first distillation column and separated therein, into a first distillation mixture in a gas phase at the top and a second distillation mixture in a liquid phase at the bottom. The first distillation mixture is condensed in the first condenser.

A novel process can be used for producing methacrylates such as methacrylic acid and/or alkyl methacrylates, in particular MMA. The process leads to an increased yield and increased efficiency compared to other C4-based production processes, in particular processes starting from isobutylene or tert-butanol as raw material. The process can be operated for longer periods without disruption and with the same or even increased activities and selectivities. The process can also be executed in a manner that is as simple, cost-effective, and environmentally friendly as possible.

Process for producing alkyl methacrylates and optionally methacrylic acid

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.

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.

Process for preparing MMA in high yields

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.

Growing community of inventors

Frankfurt-am-Main, Germany

Florian Zschunke