Catalyst Design for Selective Hydrogenation of Benzene to Cyclohexene through Density Functional Theory and Microkinetic Modeling

Cyclohexene is a chemical intermediate produced through catalytic partial hydrogenation of benzene. Density functional theory calculations and microkinetic modeling (MKM) are used to illustrate that the binding energy of benzene is a predictor of a catalyst’s cyclohexene selectivity. Brønsted-Evans-Polanyi (BEP) and scaling correlations are developed to correlate elementary reaction energetics on 3-fold active metal ensemble sites. Based on thermochemical linear relationships and BEP correlations, only benzene binding energies and H₂dissociation energies are needed in MKM to predict benzene hydrogenation activity and selectivity. MKM demonstrates that an intermediate benzene binding energy leads to an optimal balance of activity and selectivity toward cyclohexene formation. Uncertainties in the slope and intercept of BEP and scaling relationships, estimated by a Bayesian inference approach, were propagated in the MKM to quantify uncertainty in catalytic performance. Ni₅Ga₃and Ni₃Ga intermetallic compounds are predicted to be highly selective catalysts for benzene hydrogenation to cyclohexene.