Na-doped OMS-2-catalzyed highly selective aerobic oxidation of ethyl lactate to ethyl pyruvate under mild conditions

Abstract

The direct oxidation of lactate to pyruvate is an important process for catalytic conversion of biomass, although low selectivity and harsh reaction conditions limit its potential for industrial application. In this study, catalytic oxidation of ethyl lactate (EL) to ethyl pyruvate (EP) over OMS-2-based materials was conducted using O2 as the green oxidant. A 78 % EL conversion and 95 % EP selectivity were obtained in CH3NO2 at 50 °C over a Na-doped OMS-2 catalyst. The conversion and selectivity of the reaction were affected by the dopant loading of catalyst and reaction temperature. Kinetic study found that original OMS-2 showed slightly higher initial reaction rate than modified OMS-2, and the latter gave higher EP yield due to its more labile lattice oxygen. Characterization of the catalyst indicates that the enhancement of surface oxygen vacancies and reducibility from the Na-doping might contribute to the superior catalytic activity.