Preparation and Function of Layered Metallosilicate Materials

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Layered aluminosilicate and titanosilicate prepared from layered silicate kanemite have been investigated. First preparation method and basic properties of pure kanemite were established. The conditions of pillaring of kanemite by addition of tetraethylorthosilicate were studied. Consequently silica-pillared materials which have high specific surface areas and micro pores could be obtained by addition of tetraethylorthosilicate. Furthermore the layered structure as kanemite was held by the silica pillars. Al or Ti contained kanemite were prepared by addition of aluminum nitride or titanium butoxide to powdered sodium silicate or water glass. Structure ofkanemite was not destroyed by addition of Al (Si/Al>10) and Ti (Si/Ti>20). ^<27>A1-, ^<29>Si-MAS/NMR and UV-vis spectra revealed that the state of Al and Ti atoms in silica matrix shows 4-coordination numbers. XRD diffraction patterns demonstrated that the silicapillared materials maintained layered structure. The specific surface areas and pore sizes of the silica-pillared materials estimated from nitrogen adsorption were 600-1 000m^2/g and 1.4-1.5nm for aluminosilicate, 340-610m^2/g and 0.7-1.Onm for titanosilicate, respectively. These materials are microporous materials. The catalytic properties of the silica-pillared materials were investigated by IR spectra of adsorbed pyridine on the silica-pillared aluminosilicates and catalytic reaction of bromination of phenol red with H_2O_2. The silica-pillared aluminosilicates have Bronsted and Lewis acid sites. The silica-pillared titanosilicates show catalytic activity for bromination of phenol red with H_2O_2.