Synthesis and Characterization of Micro/Mesoporous Molecular

Advanced Micro- and Mesoporous Materials
eds. K. Hadjiivanov, V. Valtchev, S. Mintova, G. Vayssilov
Heron Press, Sofia, 2008
Synthesis and Characterization of
Micro/Mesoporous Molecular Sieves Prepared
from ZSM-5 Zeolite
S. Habib1 , J.-D. Comparot2 , F. Launay1 , S. Laforge2 ,
Y. Millot1 , J.-L. Paillaud3 , C. Faust3 , P. Magnoux2 ,
A. Gédéon1
1
Laboratoire Systèmes Interfaciaux à l’Echelle Nanométrique, CNRS-UMR
7142, Université Pierre et Marie Curie, case 196, 4, place Jussieu, 75252 Paris
cedex 05, France
2
Laboratoire de Catalyse en Chimie Organique, CNRS-UMR 6503, Université
de Poitiers, 40, avenue du recteur Pineau, 86022 Poitiers cedex, France
3
Laboratoire de Matériaux à Porosité Contrôlée, CNRS-UMR 7016, Ecole Nationale Supérieure de Chimie de Mulhouse, 3, rue Alfred Werner, 68093 Mulhouse cedex, France
Abstract
Zeolite/mesoporous molecular sieves of ZSM-5/Al-MCM-41 type have been
prepared using the zeolite as silica-alumina source in the presence of
cetyltrimethylammonium chloride (CTACl) under hydrothermal conditions.
The structure, cristallinity and textural properties of the synthesized samples,
as well as of the starting material, were investigated by X-ray diffraction (XRD)
and adsorption/desorption of nitrogen. The stability of the ZSM-5/MCM-41
materials was studied through their treatment in boiling water for 5 days. The
results indicate that these solids are much hydrothermally stable than the conventional Al-MCM-41 and a mechanical mixture with similar Si/Al ratio. The
addition of a silica source affords a better structuration of the mesoporous part of
the material in comparison to samples synthesized from the sole zeolite crystals.
The activity of the micro/mesoporous samples towards the acid-catalysed transformation of methylcyclohexane is compared to those of ZSM-5, Al-MCM-41
and a mechanical mixture.
1 Introduction
Microporous aluminosilicates, with their uniform channel size, unique molecular shape selectivity, as well as strong acidity and good thermal/hydrothermal
stability, have been widely used as acid catalysts. However, the slow intracrystalline diffusivity and the small micropore size of zeolites have limited their
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