The effect of palladium loading on the catalytic performance of Pd/SAPO-11 for n-decane hydroisomerization

Nanocrystalline SAPO-11 silicoaluminophosphate molecular sieves with appropriate acidic sites were successfully synthesized by a hydrothermal method using di-n-butylamine (DBA) as a template. A series of bifunctionalPd/SAPO-11 catalysts with different ratios between the accessible metal Pd sites and acid sites was prepared by adjusting the Pd loading, and the catalytic performance of the prepared samples was tested in the hydroisomerization of n-C-10. The results showed that the activity of xPd/S11 in the hydroisomerization of n-C-10 and the selectivity to i-C-10 were dependent upon both the ratio between the metal and acid sites (C-Pd/CH+) and the effective acid sites number between two metal Pd sites (n(as)) in the xPd/S11 catalysts. It was concluded that the appropriate values of C-Pd/CH+ (0.09 <= C-Pd/CH+ <= 0.27) and n(as) values of similar to 1.5, observed for the 0.1Pd/S11 and 0.3Pd/S11 bifunctional catalysts, were beneficial for the synergetic effect between hydrogenating/dehydrogenation and acid functions. The highest selectivity of 89.8% to i-C-10 was obtained at n-C-10 conversion of 90.8% over the 0.3Pd/S11 catalyst, which could be considered as an ideal Pd/SAPO-11 catalyst for n-C(10)hydroisomerization. (C) 2016 Elsevier B.V. All rights reserved.