The hydrogenation of phenol is an important industrial reaction in that it produces cyclohexanone, a key intermediate in the manufacture of nylon polymers. In our work phenol was hydrogenated in water at moderate temperatures and hydrogen pressures in a bench top reactor using polyvinylpyrrolidone (PVP) capped palladium nanoparticles. These nanoparticles were prepared using solution based colloidal methods in order to generate catalysts of a specific size. A gas chromatograph/mass spectrometer (GC/MS) was used to monitor the reaction and for comparison additional reactions were performed with a commercial 5% palladium on silica catalyst and PVP-capped palladium nanoparticles. For each catalyst the turnover frequency was determined and was used to compare catalytic activities, as well as reaction selectivity for cyclohexanone. Surface binding sites on the palladium nanoparticle surfaces are being analyzed through attenuated total reflectance infrared (ATR-IR) spectroscopy by the adsorption of carbon monoxide on the nanoparticle surface. The number of surface binding sites will be used to calculate the dispersion factor, or ratio of active surface sites to total palladium atoms, in order to “correct” the turnover frequencies. This information will allow us to determine the catalyst particle size most efficient for the formation of cyclohexanone. Through varying reaction conditions of temperature and reactant concentrations, as well as nanocatalyst particle size and PVP capping agent molar mass, we aim to elucidate the factors that influence the atomic scale design of greener and more efficient catalytic materials.

Kinetic and surface analysis of active sites in the hydrogenation of phenol using palladium nanoparticles

251st National Meeting (2016)

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