Hydrocarbons in zeolite L

Measurements have been made of the sorption of O 2 , Ar, CH 4 , C 2 H 6 , C 3 H 8 , n -C 4 H 10 , iso-C 4 H 10 , n -C 5 H 12 , neo-C 5 H 12 , n -C 6 H 14 , C 6 H 6 and cyclo-hexane in a sodium-potassium form of zeolite L. In some cases heats of inclusion have been evaluated as functions of amounts sorbed. For the n -paraffins C 1 to C 4 the initial isosteric heat q st obeyed the equation q st = 4.8 + 2.2( n − 1) kcal per mole where n denotes the number of carbon atoms. This additive property of q st indicates that it is dominated by dispersion and repulsion energy contributions. As the amount of included hydrocarbon increases, sorbate-lattice interaction is augmented by sorbate-sorbate interaction, leading to maxima in the heat curves near saturation. Saturation values appear to decrease rather rapidly with increasing temperature.