Effect of Temperature on Neopentane Isotherms Determined on Non-Porous Non-Graphitized Carbon Black (Elftex)

Abstract

Adsorption isotherms of neopentane have been determined on the non-porous non-graphitized carbon black Elftex at temperatures from 282.8 K down to 249.0 K, i.e. from the boiling point of bulk neopentane to below its freezing point. It is shown that the shape of the isotherm in the multilayer region, and hence the magnitude of the FHH r value, is not directly affected be temperature, although an indirect effect, occurring as a result of a change in the properties of the adsorbed monolayer, is observed. It is also concluded that, if the properties of an adsorbed phase are dependent on coverage, then the adsorption isostere method is unlikely to lead to reliable values for the heat of adsorption.