Enhanced catalytic activity for butane isomerization with alumina-promoted tungstated mesoporous zirconia

Mesoporous zirconia, synthesized from surfactant templating, was used to disperse alumina and tungstate as a catalyst (denoted as AW/m-ZrO₂) for the isomerization of n-butane. At a relatively low temperature of calcination (700 °C), the catalyst (AW/m-700) performed exceptionally well, both in maximum rate and stability, at a temperature of 250 °C. This was lower than the temperature needed by other tungstated zirconia-based catalysts reported so far. This lower temperature of calcination leads to the presence of more Brönsted acid sites with higher acid strength. In comparison with the normal dense phase zirconia catalyst, AW/m-ZrO₂ catalyst showed higher n-butane isomerization activity than the corresponding AW/d-ZrO₂ catalyst, which has about the same surface area. The difference in catalytic activity was attributed to the higher degree of dispersion of tungstate on the surface of m-ZrO₂.