| Abstract
| - The locations of benzene molecules inside completely siliceous ZSM-5 at various loading levels weredetermined from FT−Raman spectra of benzene adsorbed in ZSM-5. In the low loading range (1−4 molecules/u.c.), all of the guest molecules reside at the channel intersections. In the intermediate loading range (5 and6 molecules/u.c.), four benzene molecules are located at the intersections, while the remaining guest moleculesaccess the zigzag channel segments. In the high loading range (7 and 8 molecules/u.c.), four guest moleculesremain at the intersections and the rest of the benzene molecules move to the midsections of the straightchannels. The changes in the Raman spectra of both sorbate and sorbent clearly indicate that the host frameworkundergoes two successive phase transitions at the loadings of 5 and 7 molecules/u.c., respectively. The zeoliticframework vibrations also indicate that there are very strong interactions between the guest molecules andthe host framework in the high loaded phase.
|
