Combination of Reaction and Separation in Heterogeneous Catalytic Hydrogenation of Ethylformate

Abstract

Continuous hydrogenation reaction of ethyl benzoylformate was studied over a (-)-cinchonidine (CD)-modified Pt/Al2O3 catalyst. The catalyst showed a good stability, and high enantioselectivity was achieved in the fixed-bed reactor. Chromatographic separation of (R)- and (S)-ethyl mandelate originating from a post-continuous hydrogenation reaction of ethyl benzoylformate over the (-)-CD-modified Pt/Al2O3 catalyst was investigated in the same reaction mixture. A commercial column filled with a chiral selector resin was chosen as a perspective preparative-scale adsorbent. Since adsorption equilibrium isotherms were linear within the entire investigated range of concentrations, they were determined by pulse experiments for the isomers present in a post-reaction mixture. Breakthrough curves were measured and described successfully by the dispersive plug-flow model with linear driving force approximation.