AVS 46th International Symposium
    Surface Science Division Tuesday Sessions
       Session SS-TuP

Paper SS-TuP25
The Reactivity of Short Chain Alcohols on VC (100)

Tuesday, October 26, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: R.L. Guenard, University of Houston
Authors: R.L. Guenard, University of Houston
S.S. Perry, University of Houston
Correspondent: Click to Email
The reactions of small chain alcohols on the nonpolar (100) surface of single crystal VC have been studied using temperature programmed desorption (TPD). The surface was prepared by argon ion sputtering followed by electron beam heating to 1400K. The sample was sputtered and annealed between coverages, as well, in order to insure the removal of any oxides formed in the reaction with an alcohol. The results of these experiments showed that VC exhibits selective reactivity towards alcohols including, dehydrogenation and alkene formation. In these TPD measurements, methanol adsorbed both molecularly and dissociatively onto VC. The products of temperature induced desorption being H@sub2@ and CH@sub4@. A molecular desorption reaction path was also observed. For ethanol and isopropanol, the resulting products of temperature induced desorption were notably different from that of methanol. A @beta@-hydride elimination mechanism results in the formation of water and an alkene. Ethylene and water are evolved from the surface when dosed with ethanol, while propene and water are the products evolved when isopropanol is dosed. In both cases the alkene product is separated from the surface at a temperature greater than water desorption. This reactivity of short chain alcohols, observed near room temperature on VC (100), illustrates potential pathways of lubricant degradation and highlights the possible need for passivating additives.