Catalytic activity of Al₂O₃/WO₃/ZrO₂ strong solid acid catalyst for n-butane isomerization

A series of Al₂O₃/WO₃/ZrO₂ (AWZ) strong solid acid catalysts were prepared via precipitation, refluxing, impregnation, and calcination. The effects of Al₂O₃ on the structural, acidic, and redox features of WO₃/ZrO₂ (WZ) were studied. Al₂O₃ doping on tungstated zirconia made the zirconia tetragonal phase stable, prevented the growth of WO₃ particles and had less effect on the acid site strength. The n-butane isomerization was performed in a fixed-bed flow reactor. Compared with WZ, AWZ improved the isomerization conversion and the catalyst stability in the presence of hydrogen. The optimum Al loading in these catalysts was ∼ 0.5% and calcination temperature was 850°C . H₂ was essential for the satisfied performance of the catalysts. Pt/AWZ showed higher selectivity and stability than AWZ.