Gas-phase chemistry of vanadium oxide cluster cations 3. Reactions with CCl4

The reactions of selected vanadium oxide cluster cations with carbon tetrac hloride were studied using a triple quadrupole mass spectrometer coupled wi th a laser vaporization source. The vanadium oxide species VO2+, V2O4-6+, V 3O6-8+, V4O8-11+, V5O11-13+, V6O13-15+, and V7O16-18+ demonstrated several pathways for reaction with CCl4. The chloride ion transfer reaction is the dominant reaction pathway for the smaller clusters that contain three or fe wer vanadium atoms. For the larger clusters, the abstraction of two chlorin e atoms with the transfer of oxygen to the neutral reactant molecule domina tes their reactions with CCl4, leading to the production of phosgene. This is consistent with the reactions that occur over the condensed-phase vanadi um oxide catalyst for the degradation of carbon tetrachloride to phosgene a nd carbon dioxide. In addition, oxidation reactions are observed to occur m ore readily for clusters that contain vanadium atoms with oxidation states lower then +5.