Intercalation of n-alcohols in vanadium pentaoxide hydrate from the vapour phase

Abstract

The intercalation of n-alcohol molecules having carbon numbers less than eight in vanadium pentaoxide hydrate has been studied. Methanol was intercalated to form double layers by application of a stepwise intercalation isotherm. Other alcohols were intercalated at, or a little above, monolayer coverage. Methanol and ethanol are oriented in parallel with the layer sheets, while alcohols with more than two carbon atoms are oriented normal to the layer sheets. For all the alcohols having less than seven carbon atoms, ca. 0.5 mol alcohol was irreversibly intercalated by 1 mol V₂O₅, corresponding to four alcohol molecules per unit cell. These alcohols can be removed by contacting with H₂O vapour and evacuating. Alcohols with more than three carbon atoms are intercalated by two modes, one irreversibly and the other reversibly, in the interstitial spaces. Adsorption of heptan-1-ol is very slow, saturation being achieved within 10 days.