The effect of extra framework species and acid properties of dealuminated zeolitic support on the catalytic behavior of palladium in n-hexane isomerization reaction

摘要

Isomerization of n-hexane was carried out over palladium based catalysts prepared by aqueous ion exchange with dealuminated NaY-zeolite support. The dealumination was realized using acid solutions of HNO3, HCl and H2SiF6 with different concentrations. The catalysts were characterized by nitrogen physisorption, XRD, ~(27)A1 and ~(29)Si-MAS-NMR, the NH3-TPD, the H2-TPR and DRIFT. The catalytic reaction was performed in the temperature range between 498 and 548 K. The results showed that the isomer selectivity and catalytic activity of catalysts increased with increasing the Si/Al ratio of the support and, specially, with the presence of extra framework species which control the active Br0nsted and Lewis acid sites.