Catalytic hydrogenation is among the most crucial reaction processes, with particular importance in the conversion of biologically-derived molecules to higher-value chemicals. The significance of selectively transforming these highly-complex, multifunctional feedstocks motivates detailed mechanistic studies to obtain strategies for controlling the product distribution. One set of transformations attracting particularly interest is the selective hydrogenation of α,β-unsaturated aldehydes. The ability to selectively hydrogenate the C=O or C=C bond represents a substantial challenge, and is not fully understood at a molecular level.<br/><br/>In this presentation, we will discuss our approaches to heterogeneous catalyst design in the condensed phase. Using density functional theory (DFT) calculations combined with molecular dynamics simulations, we present the energetics of crotonaldehyde and cinnamaldehyde hydrogenation on model transition metal surfaces, considering gas phase models as well as microsolvation environments more representative of the liquid phase environment. We show the applicability of energy correlations in this context, drawing a link between the gas phase energetics and the more complex condensed phase representation of the environment. We provide additional insights into the structure sensitivity of these reactions, showing that the reaction energetics and selectivities depend on surface structure though the energy scaling in the presence of solvent is preserved. Together, these results provide strategies for manipulating the preferred hydrogenation selectivity.

Selective condensed phase hydrogenation of unsaturated aldehydes on transition metals: Insights from computational catalysis

ACS Spring Meeting 2021

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