Dehydration and dehydrogenation of alcohols with mononuclear cationic vanadium oxides in the gas phase and energetics of VOnH0/+ (n=2, 3)

The ion/molecule reactions of selected alcohols with the vanadium oxide cations VO+ and VO2+ are studied by Fourier-transform ion-cyclotron resonance (FT-ICR) mass spectrometry. Dehydrogenation is the dominating reaction pathway for methanol and allyl alcohols. With larger or less unsaturated alcohols, dehydration and carbocation formations prevail. While the valence in VO+ remains unchanged during alcohol dehydrogenation, VO2+ is reduced to V-III. Thermochemical data for VO2H0/+, VO3H and VO3H2+ are derived by means of ICR bracketing. The experimental results are further complemented by ab initio calculations using density functional theory.