Efficient and cost-effective catalytic hydrogenation and dimerization of alkenes are of great interest industrially. Transition metal species supported on porous materials (e.g. zeolites and metal-organic frameworks) are promising candidates for facilitating these types of reactions due to the advantages inherent in heterogeneous catalysis (e.g. better scope for catalysis separation and reusability). We are interested in using theoretical calculations to examine the mechanistic pathways for various catalytic reactions on zeolites. Insights from these calculations could lead to the development of more efficient and selective catalytic platforms. To this end, we have benchmarked the performance of density functional theory (DFT) methods for predicting the energies and barriers for the hydrogenation and dimerization of ethylene by transition metal hydride catalysts. We do this by comparing 18 different exchange-correlation functionals with couple cluster theory, CCSD(T) extrapolated to the complete basis set limit. Of the 18 functionals tested, the best functional has a mean absolute deviation (MAD) of about 4 kcal/mol from CCSD(T). We found that dispersion corrections result in only slight improvement to the MADs. Generalized gradient approximation and double hybrid functionals gave poor MADs, whereas hybrid functionals with Hartree-Fock exchange of 20-30% lead to better accuracy. We will also discuss the performance of DFT when the catalysts are supported on a zeolite support and without the support. All the DFT calculations were carried out at def2-QZVPP basis set level.

Performance of density functional theory for predicting hydrogenation and dimerization of ethylene using transition metal hydride catalysts supported on zeolites

255th National Meeting (2018)

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