NOTE ON THE DIELECTRIC CONSTANTS OF ETHYL CHLORIDE AND n-BUTANE ADSORBED ON NONPOROUS TiO2

The dielectric constants of ethyl chloride and n-butane adsorbed on nonporous TiO2 were measured. The plot of capacity change versus volume adsorbed was found to reveal two linear sections in the case of ethyl chloride with an abrupt change in the slope of the plot occurring at the Vm value calculated using the B.E.T. or Hüttig adsorption equations. With n-butane the plot was linear beyond Vm. For ethyl chloride on rutile a slight temperature dependence in the polarization was observed for the volume of gas adsorbed above Vm, while a negligible temperature dependence was noted for the portion below Vm. It is postulated that the observations with the polar gas on the nonporous rutile can be explained by a change from oscillatory to rotational motion of the adsorbed molecule after the monolayer is complete. It was noted that gases adsorbed on nonporous TiO2 behaved differently from gases adsorbed on porous silica gel. This appears to lead to the necessity of postulating changes of density for the adsorbed phase on silica gel.