Catalytic direct dehydrogenation of ethyl lactate to produce ethyl pyruvate over a synergetic Cu0/Cu+ interface

The direct dehydrogenation of ethyl lactate (EL) to produce ethyl pyruvate (EP) over non-precious heterogeneous catalysts is highly desirable, but challenging. Herein, we report a highly efficient silica-supported copper catalyst prepared via a hydrolysis-precipitation method (Cu/SiO2-HP) for the dehydrogenation of ethyl lactate, which exhibited an 85.4 % EL conversion with 91.1 % selectivity toward EP at 320 °C. XAFS, in situ XPS, and CO-adsorption FT-IR spectra revealed that the Cu/SiO2-HP catalyst had abundant Cu0/Cu+ interfaces. In situ FT-IR spectra, kinetic studies, and theoretical calculations also demonstrated that the Cu0/Cu+ interfaces synergistically activate the O−H and C−H bonds in the adsorbed EL for direct dehydrogenation into EP. The H/D kinetic isotope effect for model reaction confirmed that C−H bond activation is the key step in the dehydrogenation reaction. This study offers a new approach toward the selective conversion of EL into EP, which is of great significance for biomass conversion.