Application of the Selective Energy Transfer Model to Account for an Isokinetic Response in the Gas Phase Reductive Cleavage of Hydroxyl, Carbonyl and Carboxyl Groups from Benzene Over Nickel/Silica

Abstract

The gas phase hydrodeoxygenation of a series of aromatic alcohols, aldehydes and acids has been examined over Ni/SiO 2 . Compensation behaviour is established with an isokinetic temperature (518 ± 21 K) that is consistent with with the point of intersection of the Arrhenius lines. This is accounted for using the Selective Energy Transfer model that is based on resonance between the catalytic Ni-H vibration and out-of plane C-H vibrations of the aromatic reactants with a transferral of resonance energy from the catalyst to generate the ''activated complex''. The calculated wave number of this vibration mode is 720 ± 29 cm -1 with an associated anhamonicity of -3.3 ± 0.9 cm -1 . Our analysis suggests that the oxygenated aromatic is weakly adsorbed on the catalyst and surface mobility facilitates reaction with adsorbed hydrogen atoms.

Some tentative explanations for the enthalpy–entropy compensation effect in chemical kinetics: from experimental errors to the Hinshelwood-like model

“…The list of proposals considered hereafter does not try to be exhaustive, but only illustrative of the complexity of the problem analysed. Other plausible theoretical approximations have already been published by other authors [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21].…”

Methods and Applications of Deoxygenation for the Conversion of Biomass to Petrochemical Products

“…Most of the earlier work in HDO used sulfided forms of Mo as the active element and Co or Ni as promoters on Al2O3 [27,70,79]. However, sulfide catalyst would not work for bio-oil since the feed does not contain significant amounts of sulfur.…”

“…Therefore, investigations on new catalysts that do not require sulfidation and supports such as activated carbon that are tolerant to deactivation are needed [82]. The suitability of Ni as a catalyst to activate the dihydrogen molecule in HDO has been reported by several groups [79,83]. In comparison to noble metals, the use of Ni is extremely economical especially for large scale applications.…”

“…For example, the gas-phase hydrodeoxygenation of a series of aromatic alcohols that include aldehydes and acids has been reported with Ni/SiO2. This study analyzed kinetic effects of the gas phase hydrogenolysis of -CH2OH, -CHO and -COOH groups attached on to aromatic ring structures in the presence of Ni/SiO2 [79]. They concluded that the oxygenated aromatics get weakly adsorbed on the catalyst and the surface mobility facilitates reaction with adsorbed hydrogen atoms.…”

A SET Approach to the Interplay of Catalysts and Reactants

“…One can start with the simplest case, in which an integration over many different ways in which energy dissipation can be employed was performed. Besides these examples, some results from previous investigations on the SET theory, or leading towards SET, are presented to the reader [5][6][7][8][9][10][11][12][13][14][15][16][17].…”