الفهرس | Only 14 pages are availabe for public view |
Abstract 1. Zirconia gel was prepared by the addition of ammonium hydroxide to aqueous/or alcoholic solution of zirconyl oxynitrate at 35oC with constant vigorous stirring till pH = 8. The precipitate was washed several times with bidistilled water till free from nitrate ions. 2. 10 wt.% polymer zirconia was prepared by adding a solution containing calculated amount of polyvinyl alcohol, (PVA), to appropriate amount of zirconia gel DROPwise with constant stirring. 3. Polymer modified sulfated zirconia was prepared by adding appropriate amounts of 2N H2SO4 solution to 10 wt.% polymer zirconia to obtain samples containing 5, 10, 15, 20, 25 and 30 wt.% sulfated polymer zirconia in aqueous and alcoholic medium. 4. 10 wt.% sulfated zirconia with different polymer contents were prepared by adding calculated amounts of polyvinyl alcohol solution to 10 wt.% sulfated zirconia to obtain samples containing 5, 10, 20 and 30 wt.% polyvinyl alcohol loaded 10 wt.% sulfated zirconia. The resulting thin slurry was evaporated; the solid was pulverized and sieved to 0.41.25 mm particle size. 5. The prepared samples were calcined at 400, 500, 600 and 700oC for 4 hours. 6. Structural characterization of the catalysts and the phase changes were determined using thermal analysis and Xray techniques. 7. Textural properties were determined by measuring the adsorption of nitrogen at 196oC. 8. The total surface acidity of the catalysts was determined by applying the potentiometric titration of nbutylamine in acetonitrile. The nature of acid sites of the investigated catalysts was determined by pyridine adsorption measurements. 9. The dehydration of ethanol and dealkylation of cumene was found to depend on sulfate and polymer. |