Evonik develops new process for MMA

EVONIK has developed a more efficient process to produce methyl methacrylate (MMA), a widely-used polymer precursor, which it says is “entirely new”.

MMA is used to make Plexiglas, to make contact lenses and in adhesives, amongst other things. Evonik says that its new process has high yields, has only low energy requirements and produces significantly less wastewater than conventional processes. The company is currently testing the process, which it has dubbed “LiMA”, at a pilot plant in Darmstadt, and has proven that the MMA is of excellent quality.

LiMA is proprietary, so Evonik has not released precise details of the process, but says that it combined established process techniques with new process designs. The process converts ethylene and methanol into methacrolein in multiple steps. Converting methacrolein into MMA is then carried out in the liquid phase in a single step using a new, proprietary catalyst system. Generally, MMA catalysts gradually lose individual components in the reaction, a process known as ‘bleeding’. However, this is minimal with the LiMA catalysts, due to a special preparation procedure and the combination of metal oxides used. The preliminary process stages removes by-products and catalyst poisons, further contributing to the efficiency.

Evonik says that the reaction conditions are “moderate”, with temperatures well under 100˚C, and the equipment used requires minimal engineering and maintenance. Steffen Krill, the head of methacrylates innovation management at Evonik says that the process is the most efficient MMA production method yet discovered. Yields are as high as 90%, and because energy use is so much lower, 40% less CO₂ is produced.

“The product can be used for optical applications without limitations – and that’s traditionally one of the most demanding applications for engineering-grade plastics,” said Krill.

Evonik is one of the world’s leading methacrylate monomer producers, but generally focuses on C3 monomer technology, using acetone, and C4 monomer technology, using isobutene. The new technology is a C2 technology.