Structural investigations on zeolitic faujasite/benzene host/guest systems (Si/Al = 2.43 and ≈ 200) by using combined powder diffraction, adsorption calorimetry and molecular mechanics simulations

The NaY(Si/Al =2.43)/benzene (1) and DAY(Si/Al ≈ 200)/benzene (2) systems are investigated by combined adsorption calorimetry, X-ray or neutron powder diffraction and computer simulation techniques. For (1) and (2) a good estimation of the sorption heats is obtained. A complementary study of a prehydrated NaY/benzene (3) system is also realized. For (1), (2) and (3) the BZ(C)/BZ(W) ratios, the distributions (localization and population) of these two independent sorbate species and the variations of the cubic unit-cell parameters are given. In (3) two ordered WI′ and WII water species exist and their distributions are reported. For this system a substantial cation migration is evidenced. In (2) two independent and totally disordered benzene species exist. It is concluded that adsorption calorimetry yields decisive informations on the adsorption mechanisms.