EXTRACTIVE WORKUP OF A SODIUM-SALT-CONTAINING MMA-METHANOL MIXTURE

摘要

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 constituent 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 discharge of 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. This process moreover has the advantage that fewer demands than described in the prior art are placed on plant apparatus configuration.