Effects of W content on the isomerization performance of solid super acid Pd-SO₄^2-/ZrO₂-WO₃

The effects of W content on the performance of the Pd-SO₄^2-/ZrO₂-WO₃ solid super acid catalyst was studied using n-pentane isomerization as a probe reaction and the catalysts were characterized by X-ray diffraction(XRD), FT-IR, H₂-TPR, specific surface area measurements(BET), thermogravimetry-differential thermal analysis(TG-DTA) and NH₃ temperature-programmed desorption(NH₃-TPD). The effects of WO₃ content on the acidity, surface area and crystal structure of catalyst were researched. The catalytic activity of the Pd-SO₄^2-/ZrO₂-WO₃ solid super acid catalyst with a mass fraction of 13% WO₃ which was calcinated at 600℃ was found to be the best. At reaction temperature of 260℃,space velocity of 1.0h^-1,H₂/ n-pentane mol ration of 4.0 and reaction pressure of 2.0MPa, the iso-pentane yield was 40.1%. The iso-pentane yield was stabilized in about 38% and the selectivity is higher than 95.3％within 80h .