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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