Pore Structure and Surface Acidity Effects of Ordered Mesoporous Supports on Enantioselective Hydrogenation of Ethyl Pyruvate

Abstract The enantioselective hydrogenation of ethyl pyruvate is studied using cinchonidine‐modified platinum supported on ordered mesoporous materials as a catalyst. The influence of different pore structures and hence, textural properties of the support on the enantiodifferentiation is investigated. The selected representative model supports are SBA‐15, SBA‐16, and KIT‐6. Depending on the pore structure, varying enantioselectivities are obtained. Furthermore, SBA‐15 is post‐synthetically aluminated to produce materials with different Si/Al ratios. An increase in Al content leads to an increased support surface acidity and enhanced enantioselectivity. The catalyst samples are characterized by small‐angle X‐ray scattering (SAXS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), temperature‐programmed desorption of ammonia (TPAD), and N 2 and CO sorption techniques. Applying optimized reaction conditions resulted in enantiomeric excesses of ( R )‐ethyl lactate of 90–94 % ee at total conversion.