Hydrogenation of Cinnamaldehyde over Pd/Al2O3 Catalysts Modified with Thiol Monolayers

Modification of supported Pt catalysts with thiols has recently been shown to improve the hydrogenation selectivity of α,β-unsaturated aldehydes to unsaturated alcohols. Here, we apply a variety of organic thiol coatings to Pd/Al₂O₃ catalysts that typically have a much lower intrinsic selectivity for desired product formation. Thiol monolayers were found to increase hydrogenation selectivity to cinnamyl alcohol; however, unlike with Pt catalysts, the increase was independent of the identity of the organic tail.