سال انتشار: ۱۳۸۷

محل انتشار: همایش بین المللی ژئولیت ایران

تعداد صفحات: ۵

نویسنده(ها):

Roozbeh J. Kalbasi – Department of Chemistry, Islamic Azad University, Shahreza Branch, Isfahan, Iran
ahmadreza massah – Department of Chemistry, Islamic Azad University, Shahreza Branch, Isfahan, Iran
mehran ghiaci – Department of Chemistry, Isfahan University of Technology, Isfahan, Iran

چکیده:

The nitration of toluene has been studied in the vapor-phase at various temperature over a series of
surface modified and unmodified ZSM-5 (Si/Al = 60-170) loaded with H3PO4, differing in the external
surface treatment of the zeolites. All samples were characterized by element chemical analysis, X-ray
diffraction, N2 physisorption, thermal analyses and FT-IR.. When the external surface of the zeolite is
blocked with a surfactant before loading it with H3PO4, the selectivity to form the 4-nitrotoluene was higher.
This superior performance of the externally blocked catalysts, relative to the unmodified H3PO4/ZSM-5
catalyst, shows that by blocking the external surface area of the ZSM-5 support, it exhibits a superior
catalytic selectivity than the unmodified catalyst. Catalysts containing 0–۴٫۹ wt.% P were prepared using
modified and unmodified ZSM-5 zeolites, and their catalytic performance for vapor phase nitration of
toluene to 4-nitrotoluene (4-NT), 2-nitrotoluene (2-NT) and oxidation products was determined. The effect
of reaction temperature, H3PO4 content, feed ratio of HNO3 to toluene, WHSV and carrier gas flow rate was
also investigated.