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۱Application of zeolite beta as a valuable and non–toxic catalyst for the synthesis of acylals
اطلاعات انتشار: همایش بین المللی ژئولیت ایران، سال
تعداد صفحات: ۷
Zeolite beta with Si\Al ratio of 100 was synthesized using tetraethylammonium hydroxide (TEAOH) as
the structure–directing agent (SDA) in the absence of alkali metal cations. Zeolie beta was found to be an
effective Lewis acid catalyst for the conversion of aldehydes into acylals with excellent chemoselectivity
under solvent free conditions.<\div>

۲Vapor phase esterifation of acetic acid with n–butanol over H3PO4\MCM–41
اطلاعات انتشار: همایش بین المللی ژئولیت ایران، سال
تعداد صفحات: ۵
Several mesoporous aluminosilicate molecular sieves with the MCM–41 structure (SiO2\Al2O3 = 20–200)
have been synthesized using different aluminum sources and modifying several synthesis parameters during
the preparation process, such as the temperature and the content of water and sulphuric acid in the gel
mixture. All samples were characterized by element chemical analysis, X–ray diffraction, N2 physisorption,
thermal analyses and electron microscopy. These Al–MCM–41 materials have BET surface areas up to 1000
m2\g. The catalytic properties of their H3PO4–treated derivatives for esterification of acetic acid with nbutanol
have been evaluated. This reaction preferentially gave n–butyl acetate. The conversion of acetic acid
to n–butyl acetate increased with increasing the H3PO4 content in the catalysts and reached a maximum value
for a H3PO4 loading of 20%, a further increase in H3PO4 leading to a decrease in the activity for
esterification. The acidic properties and the pore network of the catalysts were key factors conditioning their
catalytic performance. The effect of reaction temperature, H3PO4 content, feed ratio of acetic acid to nbutanol,
WHSV and carrier gas flow rate was also investigated.<\div>

۳Highly selective vapor phase nitration of toluene to 4–nitro toluene using modified and unmodified H3PO4\ZSM–5
اطلاعات انتشار: همایش بین المللی ژئولیت ایران، سال
تعداد صفحات: ۵
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 0–4.9 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.<\div>
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