الفهرس 
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Abstract
1. For the preparation of H3PW12O40 (TPA)-supported tin oxide catalysts, The Sn(OH)4.xH2O gel was first dried at 120°C for 24 h, then calcined at 550°C for 4 h. A series of catalysts with different TPA loading (3, 7, 10, 15, 25 and 30wt %) was prepared with constant stirring. The excess water was removed at 70°C under vacuum. 2. For the preparation of SO42-/SnO2 catalysts, the Sn(OH)4.xH2O gels were impregnated with the appropriate amount of 2N H2SO4 solution to obtain 5, 10, 15, 25 and 30 wt.% sulfates with constant stirring. 3. All of the prepared catalyst samples were dried at 120°C over night, then calcined at 400, 500 and 600oC for 4 hours. 4. Structural characterization of the prepared catalysts and the phase changes were determined using thermal analysis and X-ray techniques. 5. Textural properties were determined by measuring the adsorption of nitrogen at -196oC using conventional volumetric apparatus. 6. The total surface acidity of the catalysts was determined by applying the potentiometric titration of n-butylamine in acetonitrile. The nature of acid sites of the investigated catalysts was determined by pyridine adsorption measurements. 7. The catalytic activity was measured by Pechmann reaction.