Determination of mass transfer and thermodynamic properties of branched paraffins in silicalite by inverse chromatography technique

Equilibrium isotherms and effective diffusivities of 3-methylpentane, isopentane, and 2,2-dimethylbutane were measured between 150 and 300 degreesC by a linear inverse chromatography technique. The validity of the equilibrium data was checked with gravimetric experiments, and both sets of data are in good agreement. The activation energies determined from the variation of the self-diffusivities with temperature lie in the range of literature results. The following trend was observed for the self-diffusivities: isopentane > 3-methylpentane >2,2-dimethylbutane. The effective diffusivities of these compounds were found to increase with the adsorbed-phase loadings according to Darken's law for a loading ratio less than 0.7. Above this value, the diffusivities are higher than those given by Darken's law.