Gas-Phase Chemistry of Vanadium Oxide Cluster Cations 3. Reactions with CCl₄

The reactions of selected vanadium oxide cluster cations with carbon tetrachloride were studied using a triple quadrupole mass spectrometer coupled with a laser vaporization source. The vanadium oxide species VO 2 +, V 2 O 4 - 6 +, V 3 O 6 - 8 +, V 4 O 8 - 11 +, V 5 O 11 - 13 +, V 6 O 13 - 15 +, and V 7 O 16 - 18 + demonstrated several pathways for reaction with CCl 4 . The chloride ion transfer reaction is the dominant reaction pathway for the smaller clusters that contain three or fewer vanadium atoms. For the larger clusters, the abstraction of two chlorine atoms with the transfer of oxygen to the neutral reactant molecule dominates their reactions with CCl 4, leading to the production of phosgene. This is consistent with the reactions that occur over the condensed-phase vanadium oxide catalyst for the degradation of carbon tetrachloride to phosgene and carbon dioxide. In addition, oxidation reactions are observed to occur more readily for clusters that contain vanadium atoms with oxidation states lower then +5.