One‐step synthesis of ordered Sn‐substituted SBA‐16 mesoporous materials using prepared silica source of rice husk and their selectively catalytic activity

Highly ordered SBA‐16 silica mesoporous materials were synthesised hydro‐solvothermally under the acidic medium using SiO₂/F127/BuOH/HCl/H₂O gel. Pure SiO₂ powders were prepared from inexpensive and environmentally friendly silica source of rice husk. The pore size of the materials could be optimised by using a blend of P123 and F127 templates. Sn‐substituted SBA‐16 mesoporous materials were yielded via the direct injection of stannic chloride into the fixed gel in acidic medium. X‐ray diffraction, N₂ adsorption, scanning electron microscope/transmission electron microscope results suggest that tin ions were incorporated into the Si‐SBA‐16 framework by isomorphous substitution between Sn and Si ions. Elemental analysis indicates that tin can be substituted in the range of Si/Sn = 21.4–10.5. UV–vis, XPS, TPR‐H₂, TPD‐NH₃ results reveal that tin atoms are highly dispersed in 4+ oxidation state and mostly occupy in the silica framework. The degree of tin incorporation into silica framework can easily be controlled by a simply adjustment of the H₂O and HCl molar ratios. The mesoporous Sn‐SBA‐16 materials were an active benzylation catalyst with almost 100% selectivity to monoalkylated product in alkylation of aromatics with benzyl chloride. © 2011 Canadian Society for Chemical Engineering