Enantioselective hydrogenation of ethyl benzoylformate, from mechanism and kinetics to continuous reactor technology

The enantioselective hydrogenation of ethyl benzoylformate over (−)-cinchonidine (CD)-modified Pt/Al₂O₃ catalyst in semi-batch and continuous fixed bed reactors was studied as a function of the modifier concentration and reaction temperature. The kinetic results from the semibatch reactor showed a higher enantioselectivity and lower initial rate as the amount of modifier was increased. The results from the fixed bed reactor demonstrates that continuous enantioselective hydrogenation is possible and that continuous feeding of (−)-CD is needed to maintain a high steady-state enantioselectivity.