Computational investigation of isoeugenol transformations on a platinum cluster – I: Direct deoxygenation to propylcyclohexane

The growing demand for renewable and sustainable fuels, protagonists of an increasingly important research area due to the exhaustion of fossil resources, has oriented our investigation towards the computational mechanistic analysis of the catalytic hydrodeoxygenation (HDO) reaction of isoeugenol. Having the most com­ mon functional groups, the isoeugenol molecule is actually considered as an experimental and computational model for typical species of biomass origin. The reported computational investigation outlines the energy bar­ riers and the intermediates along the path for the conversion of isoeugenol to propylcyclohexane through a direct deoxygenation mechanims, catalyzed by a subnanometric metal cluster. For this purpose, the Pt10 platinum cluster was chosen as the catalyst model, being this noble metal a reference for hydrogenation reaction. The results obtained rule the formation of the 4-propylphenol intermediate as the rate determining step for the considered branch of the mechanim, and as the pivotal point for further ramifications. The present is the first of a series of studies aimed to a complete mapping of isoeugenol HDO on a Pt cluster, to be used as reference for further, more focused, investigations, such as those regarding the effects of the support and of the metal particle size, as well as the HDO reaction of biomass-derived compounds similar to isoeugenol.