Cinchonidine doped Pd catalysts in the enantioselective hydrogenation of (E)-2-methyl-2-butenoic acid

Commercial 5 wt.% Pd-containing catalysts doped with cinchonidine were investigated in the enantioselective hydrogenation of (E)-2-methyl-2-butenoic acid (P = 4.0 MPa of H2, T = 298 K) with the aim of determining how the activity and enantioselectivity may be affected by specifications of the catalytic system (metal dispersion, support acidity and surface area).

Graphical abstractCommercial Pd (5 wt.%) catalysts doped with cinchonidine (CD) were investigated in the enantioselective hydrogenation of (E)-2-methyl-2-butenoic acid (P = 4.0 MPa of H2, T = 298 K) with the aim of determining how the enantioselectivity and TON may be affected by specifications of the catalytic system (support acidity, surface area, metal dispersion and particle size). A significant importance seems to be the size of the Pd clusters, influencing the total or partial covering of the catalytic surface by the modifier. Furthermore the acidity of the support favours the adsorption of CD, and the stronger this interaction is the more stable the anchoring of the modifier is during the reaction. Figure optionsDownload full-size imageDownload as PowerPoint slide