HIGH-TEMPERATURE LOW-PRESSURE ADSORPTION OF BRANCHED C-5-C-8 ALKANES ON ZEOLITE-BETA, ZSM-5, ZSM-22, ZEOLITE-Y, AND MORDENITE

Henry constants, low-coverage adsorption enthalpies, van't Hoff preexp onential factors, and separation factors of C-5-C-8 alkanes are determ ined on beta, ZSM-5, ZSM-22, mordenite, and Y zeolites at 473-648 K us ing tracer and perturbation chromatographic techniques. Three differen t adsorption behaviors were encountered depending on the zeolite type: (1) nonselective competitive adsorption of isoalkanes and n-alkanes i nside the micropores (zeolite Y), (2) preferential adsorption of the n -alkanes over the isoalkanes inside the micropores (beta, ZSM-5 and mo rdenite), and (3) selective adsorption of the n-alkanes in the micropo res and of the isoalkanes on the external crystal surfaces (ZSM-22). L inear and mono-and multibranched alkanes can be separated on columns o f ZSM-22 and beta zeolites.