Mesoporous WO₃-CeO₂-ZrO₂ solid superacid catalyst is based on zirconium oxide as the main component, by introducing a rare earth element Ce to maintain a stable tetragonal phase of ZrO₂; WO₃ as an accelerator to replace sulfate and avoid the loss of sulfate to cause deactivating; at the same time, the introducing of mesoporous structure will get  high mesoporous material surface area and pore volume to have more active center, stronger adsorption and mass transfer, thus to get access to mesoporous with high catalytic activity composite solid superacid. Solid superacid refers to the solid acid with its strength greater than 100% of concentrated sulfuric acid, that is, its Hammett acidity function H0≤-11.93. Solid superacid has strong acid, good activity, high selectivity, easy to separate from the product, does not corrode equipment, little environmental pollution, is a green and efficient, safety and environmental protection of the new catalyst.

 

Mesoporous WO₃-CeO₂-ZrO₂ solid superacid catalyst preparation method is as bellowing:

1. Weigh a certain amount of ZrOCl₂ • 8H₂O and ammonium paratungstate, adding an appropriate amount of deionized water to dissolve, heat and reflux for 2 hours, and cooling to obtain the solution A;

2. Weigh the amount of cerium nitrate hexahydrate, and add deionized water to give solution B, add dropwise B into A a with stirring, to obtain the solution C;

3. Weigh a quantity of CTAB templating agent, add deionized water and stir to dissolve, then it was added dropwise into the solution C with stirring slowly and keep stirring for 2 hours after finished;

4. Slowly adding aqueous ammonia dropwise with stirring until the pH value becomes to 11.0 and stirring continually for 4 hours, then turning into the reactor to carry out hydrothermal reaction at 110℃ for 60h, suction filtered after cooling, washing the precipitate with deionized water and a small amount of anhydrous ethanol, and dried milled to obtain the precursor;

5. Heat the precursor to a certain temperature at the heating rate of 1℃/min, thermal insulation for 3 hours, finally we get the mesoporous WO₃-CeO₂-ZrO₂ (WCZ) solid superacid.

 

Studies have shown that mesoporous WO₃-CeO₂-ZrO₂ solid superacid catalyst which obtained under the optimum conditions has the conversion rate of acetic acid up to 97.28%, and the conversion is still very high after multiple uses, which indicates that the catalyst not only has high catalytic activity, but also has excellent reusability.