Key intermediates in the hydrogenation of carboxylic acids over Pt-ReOx/TiO2 catalyst

The reactivity of different forms of adsorbed acetic acid on the Pt-ReOx/TiO2 catalyst was studied. To this end, in situ FTIR spectroscopy at T = 200 °С was used to identify three forms of adsorbed acetic acid: bidentate acetates and two forms of molecularly adsorbed acetic acid (1645–1653 and 1700–1720 cm–1). Rate constants for the consumption of two forms of molecularly adsorbed acetic acid, which are equal to 0.029 and 0.02 s–1, respectively, were found to be close to the rate constant of the catalytic reaction equal to 0.034 s–1, which was measured at T = 200 °С. It was concluded that two forms of molecularly adsorbed acetic acid serve as the key intermediates in the hydrogenation of acetic acid over Pt-ReOx/TiO2 catalyst.