Study of Ir/Ti-SBA-15 acidity influence on the HDN of indole.

Abstract

The hydrodenitrogenation of Indole has been studied over a series of Ti-modified SBA-15 supports and their respective Ir-catalysts. Ti-SBA-15 was synthesized using sol-gel method and Ti was added during the synthesis using TEOT as Ti source. Ti was incorporated into the framework replacing the Si atoms in the mesoporous structure. Ir/Ti-SBA-15 with and without F and/or Al were prepared to improve the catalytic activity. F and Al have been incorporated by wetness impregnation method. The effect of the incorporation of F and Al in the mesoporous structure was tested in the hydrodenitrogenation reaction of indole. The catalysts were extensively characterized by X-ray diffraction (XRD), N2 adsorption isotherms, TEM, FTIR and UV-vis-DRS and Raman spectroscopy. The low angle X-ray analysis showed for all the materials intensive reflection, characteristic of SBA-15 structure. The mesoporous structure was maintained after F and Al incorporation. The results showed that Ti incorporation reduces significantly the cluster size and improves considerably the Ir cluster dispersion. The catalytic activity of Ir/Ti-SBA-15 modified with F and Al, with higher acidity, avoided the irreversible adsorption of indole. The catalytic activity was studied in a 4563 Parr reactor, at 250°C, 15 atm of pressure of hydrogen and 360 rpm. The catalysts synthesized had good activity measured in hydrodenitrogenation of indole at mild conditions. The preliminary results show these materials as promising catalysts for HDN reactions