The mechanism of the hydrogenation of acetonitrile (CH<sub>3</sub>CN and CD<sub>3</sub>CN) to amines over a platinum film and Pt/Al2O3 catalyst was investigated by in situ infrared spectroscopy. The reaction was studied under realistic conditions -liquid phase with toluene as solvent- using a flow-through cell-microreactor in attenuated total reflection (ATR) mode developed in our research group. Reaction intermediates were identified combining infrared spectra with theoretical modeling by DFT. A sequential hydrogenation mechanism is proposed. Acetonitrile linearly and 2-fold chemisorbed on platinum sites is hydrogenated to form an imine surface intermediate (CH3CH=NH), which is hydrogenated to ethylamine. In turn, this imine intermediate can condense producing diethylamine and triethylamine and ammonia as a by-product. The time-evolution of the IR signals were modeled using a proposed microkinetic mechanism and intrinsic kinetic constants were obtained under chemical control.

Mechanism of the acetonitrile hydrogenation to amines over a platinum catalyst investigated by in situ infrared spectroscopy and DFT modeling

255th National Meeting (2018)

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