Reactions of Neutral Vanadium Oxide Clusters with Methanol

Abstract

Reactions of neutral vanadium oxide clusters with methanol and ethanol in a fast-flow reactor are investigated by time-of-flight mass spectrometry. Single-photon ionization through soft X-ray (46.9 nm, 26.5 eV) and vacuum ultraviolet (VUV, 118 nm, 10.5 eV) lasers is employed to detect both neutral cluster distributions and reaction products. In order to distinguish isomeric products generated in the reactions V(m)O(n) + CH(3)OH, partially deuterated methanol (CD(3)OH) is also used as a reactant in the experiments. Association products are observed for most vanadium oxide clusters in reaction with methanol. Products VOD, V(2)O(3)D, V(3)O(6)D, and V(4)O(9)D are observed for oxygen-deficient vanadium oxide clusters reacting with methanol, while oxygen-rich and the most stable clusters can extract more than one hydrogen atom (H/D) from CD(3)OH to form products VO(2)DH(0,1), V(2)O(4)DH(0,1), V(2)O(5)DH(0,1), V(3)O(7)DH(0,1), and V(4)O(10)DH(0,1). Species VO(2)(CH(3))(2), VO(3)(CH(3))(2), V(2)O(5)(CH(3))(2), V(3)O(7)(CH(3))(2), and V(3)O(8)(CH(3))(2) are identified as some of the main products generated from a dehydration reaction for V(m)O(n) + CH(3)OH. A minor reaction channel that generates VOCH(2)O (VOCD(2)O) and VO(2)CH(2)O (VO(2)CD(2)O) can also be identified. An obviously different behavior appears in the reaction V(m)O(n) + C(2)H(5)OH. The main observed products for this reaction are association products of the form V(m)O(n)C(2)H(5)OH. In order to explore the mechanism of V(m)O(n) + CH(3)OH reactions, DFT calculations are performed to study the reaction pathways of VO(2) + CH(3)OH and VO + CH(3)OH reaction systems. The calculation results are in good agreement with the experimental observations.