n-Hexane skeletal isomerization over sulfated zirconia catalysts with different Lewis acidity

The n-hexane skeletal isomerization over Pt/SO42−/Al2O3/ZrO2 catalysts with different density of Lewis acid sites has been studied in a fixed-bed reactor. The acidity of the catalysts was characterized by FTIR spectroscopy of low temperature CO adsorption. The calculation of the rate constants, characterizing the catalyst activity and selectivity was performed on the base of mathematical model of plug flow reactor. It was shown that the rate of hexane isomerization is mainly determined by the density of Lewis acid sites on the surface of sulfated zirconia catalysts: rate constant of n-hexane isomerization for catalyst with Lewis acidity 250 μmol g−1 is four-fold as that for catalyst with concentration of Lewis acid sites 150 μmol g−1 and the rate constant of desired product (2,2-dimethylbutane) formation is also higher by two times.