|Budget Amount *help
¥2,200,000 (Direct Cost : ¥2,200,000)
Fiscal Year 1996 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1995 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1994 : ¥1,400,000 (Direct Cost : ¥1,400,000)
The interaction between small molecules and hydroxyl groups in the cages of H-form zeolites was systematically investigated by means of in-situ transmission infrared spectroscopy. The main purpose of this research is to clarify the fundamental processes taking place in zeolite catalysis, which would give the fundamental understanding of the acidity of zeolites at molecular level.
(1) The Interaction between small and weakly basic molecules : The interaction of diatomic molecules such as H_2, O_2, and N_2, and rare gases such as He, Ar, Kr and Xe with the representative H-form zeolites, H-MOR,H-Y and H-ZSM-5 were investigated. These molecules except for He form hydrogen bonding with the acidic OH groups. It was revealed out that we can characterize the acidity of the zeolites using the IR data of the interaction.
(2) The characteristics of N_2 as a probe molecules of the acid sites in zeolites : We have revealed out that N_2 can be used as the probe of acid sites. The characteristic of N_2 as the probe was examined in detail. Since N_2 is very weak base and unreactive, it serves as an excellent new type of the probe molecule that probes only the strong acid sites without changing the intrinsic nature of the acid sites. Its nature was compared with that of CO that has been widely used as the probe recent years.
(3) The absorption and reaction of the reactive molecules on the acid sites of zeolites : By using H_2, ^<18>O as absorbate, the main feature of the IR bands observed for the water adsorption was conclusively attributed to the H-bonded adsorption. The dynamic processes of the methanol conversion to dimethyl ether and the H/D exchange reaction between water and the acidic hydroxy groups were followed by means of rapid-scanning FT-IR spectroscopy.