Theoretical Studies of Activation Energies and Pre-Exponential Factors of Alcohol Dehydrogenation on Cu

We study the thermodynamic and kinetic processes involved in the anhydrous dehydrogenation of linear-chain alcohols on the Cu(110) surface using multiscale approaches. We determine the kinetic barriers for the two dehydrogenation steps, namely, the O–H and the subsequent C–H bond-breaking on Cu. The reaction of methoxy-to-formaldehyde has a rather high-energy transition state, in contrast to that of alkoxide-to-aldehyde in the longer-chain systems. This difference qualitatively explains the lower production efficiency of formaldehyde on Cu. We also use a Monte Carlo sampling to calculate the entropies of initial and transition states. The estimated pre-exponential factors, beyond the harmonic approximation, are found to have a molecular size dependence.