ABSTRACT
A facile posthydrothermal treated process has been successfully established for restructuring of silica-pillared clay. This approach involves the hydrothermal treated process utilizing octadecylamine as structural agency followed by calcination at high temperatures. The formation of expanded interlayered mesopores is a result of treatment with octadecylamine hydrothermal conditions. The following calcination at higher temperatures gives silica-pillared clay larger pore volume and conserved high surface area. The kind of pore expansion process has been confirmed by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), N2 adsorption-desorption isotherms and transmission electron microscopy (TEM). The pore expansion mechanism of silica-pillared clay is proposed. The pore expanded silica-pillared clay has been used as the catalytic supports for H3PW12O40 loading as high as 26.9%, 35.8% and 48.2% for oxidation reaction of cyclohexene using H2O2 as oxidant. The stable charge force between H3PW12O40 and negative charged clay layers, together with big and open porous structure, large pore volume, and high loading of H3PW12O40 contributes to the efficiency conversion, high selectivity toward cyclohexene epoxide and brilliant reusability.
