A Combined Experimental and Computational Study of the Selective Hydrogenation of Acrolein On Supported Silver Alloy Catalysts

α, β–unsaturated alcohols are important intermediates in the production of fine chemicals, flavors, perfumes and pharmaceuticals. Selective hydrogenation of α,β–unsaturated aldehydes is a promising way to produce these alcohols. However, selective hydrogenation of the aldehydes to form the alcohols requires tight kinetic control since the hydrogenation of C=C bond is thermodynamically favored. Acrolein (the smallest α,β–unsaturated aldehyde) was chosen as a model compound to study the selectivity between double bond hydrogenation and hydrogenation of the aldehyde functionality.

We have undertaken a detailed kinetic study of acrolein hydrogenation over silica supported Ag and Ag alloy (AgIn, AgAu) catalysts. We have found that particle size is a key controlling factor in determining the selectivity to allyl alcohol.  8 nm Ag particles possessed a 30% selectivity to allyl alcohol at atmospheric pressure whereas 2.5 nm Ag particles showed no alcohol production.  Density functional theory studies of acrolein hydrogenation have been carried out over Ag and AgIn alloy surfaces are used to help explain the results.