| Popis: |
A method for preparing Ti-pillared montmorillonite with narrow distributed micropore size and high surface area was developed. The pillaring agent was prepared by mixing a TiC14 ethanol solution with a solution of glycerin and water. Basal spacings of 21.3 A, 17.7 A and 17.4 A, corresponding to interlayer spaces of 10.8, 8.2 and 7.9 A, were observed for the as-sythesized, 773 and 973 K calcined samples, respectively. These distances implied that Ti was incorporated into the interlayers in some form of polynuclear clusters. The 573-773 K calcined samples contained both micro- and meso-porous structures, with the former contributed ca. 88% of its total pore volume. The presence of glycerin in the preparation procedure was found to be essential in order to prepare Ti-pillared clay of high crystallinity and narrow distributed micropore size. Its role was proposed to slow down the hydrolysis of titanium ethoxide species so that titanium polyoxo clusters of more homogeneously distributed sizes could be formed during the pillaring process. The acidity and shape-selectivity of the resultant Ti-PILC were also examined. |
