INTRACLUSTER ION-MOLECULE REACTIONS IN M(+)(CH3OH)(N) WHERE M=NA OR CS

The dehydration of methanol and three deuterated isotopomers (CH3OD, C D3OH, and CD3OD) in M(+)(CH3-OH)(N), M = Cs or Na, cluster ions has be en studied. The cluster ions are produced by collision of large neutra l methanol clusters formed in a supersonic expansion with alkali metal ions. The energy imparted to the cluster by the collision and subsequ ent solvation is sufficient to induce reaction. The reaction was follo wed by comparing the intensities of M(+)(CH3OH)(N-2) (H2O) product pea ks with the intensities of the patent M(+)(CH3OH)(N) peaks. A strong d ependence of the extent of reaction on cluster size was observed. A mi nimum of twelve methanol molecules was necessary for the reaction to p roceed in Cs+(CH3OH)(N) and a minimum of eight was necessary in Na+(CH 3OH)(N). Isotopomers of methanol were used to confirm the identity of reaction products and to help suggest a reaction mechanism. When CH3OH and CD3OH clusters are produced, the exclusive products of dehydratio n are H2O and CH3OCH3 and CD3-OCD3, respectively. However, when CH3OD and CD3OD clusters are produced, the products are D2O and the correspo nding symmetric ethers. We propose a possible reaction mechanism for t he alkali ion catalyzed dehydration of methanol in the cluster ions.