Methyl Lactate From Sugar, Catalytically

A catalytic process that converts plant sugars to the industrially useful compound methyl lactate offers a potential alternative to fermentation processing. It also adds to the strategies being developed to use biomass rather than petroleum to produce commodity chemicals (Science 2010, 328, 602). Fermentation currently dominates the processes used to derivatize carbohydrates from plants, in part because carbohydrates’ thermal instability usually requires low processing temperatures. On the other hand, catalytic processes are more tolerant of temperature and concentration extremes. Esben Taarning, Martin Spangsberg Holm, and Shunmugavel Saravanamurugan at the Technical University of Denmark report that the Lewis acid zeolite catalyst Sn-beta suspended in methanol readily converts fructose, glucose, and sucrose into methyl lactate. Sucrose conversion reached 68%, the researchers report, and the catalyst can be reused multiple times. But the process has some drawbacks, cautions Michael E. Himmel of the Department of Energy’s National Renewable Energy Laboratory, including the need for relatively high temperatures (160 °C), which can increase energy costs. Additionally, the catalyst must be recovered by filtering, which can drive up solvent use. Still, Taarning says, “this paves the way for designing more economical processes for the production of chemicals from biomass.”