Lactic acid production from glucose over polymer catalysts in aqueous alkaline solution under mild conditions

Abstract

Methods for the transformation of carbohydrates into lactic acid (LA), which is a versatile platform chemical, have been widely investigated. These methods typically employ harsh reaction conditions, especially when water is used as a solvent. In the present study, a one-pot route that uses polymerizates of imidazole and epichlorohydrin ([IMEP]Cl) as catalysts to convert glucose to LA in water was described. The highest LA yield of 63% (mol%) was achieved with 99% glucose conversion at 100 °C in 50 mM NaOH solution. Compared to previous reports, the process has lower reaction temperatures and lower concentration of alkaline. A possible reaction mechanism was proposed that the coordination between the weak Lewis acid centers of the polymer with the electronegative oxygens on the intermediates efficiently facilitated the rate determining step during the reaction. This route allows for facile catalyst recovery and recycling while providing a new strategy for carbohydrate conversion.