Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 2, pp. 236−242.
Pleiades Publishing, Ltd., 2009.
Original Russian Text
L.A. Belaya, V.P. Doronin, T.P. Sorokina, T.I. Gulyaeva, 2009, published in Zhurnal Prikladnoi Khimii, 2009, Vol. 82, No. 2,
OF SYSTEMS AND PROCESSES
Thermal Stability of Zeolites Y and ZSM-5 in Matrices
of Various Compositions
L. A. Belaya, V. P. Doronin, T. P. Sorokina, and T. I. Gulyaeva
Institute of Problems of Hydrocarbon Processing, Siberian Branch, Russian Academy of Sciences, Omsk, Russia
Received May 16, 2008
Abstract—Stability of the crystal structure of zeolites Y and ZSM-5 in the presence of the most frequently used
matrix components was studied under conditions of thermal and hydrothermal treatments at high temperatures.
Modern zeolite-containing catalysts are composite
materials constituted by a matrix including a binder
and a ﬁ ller and an active component, zeolite. Zeolites
of Y and ZSM-5 types are widely used as active
components of catalysts in deep cracking of crude
oil, hydrodeparaffinization, and hydrocracking.
These processes occur at high temperatures and
also in the presence of steam, as, e.g., in the case of
catalyst regeneration in cracking processes. Therefore,
development of thermally stable and highly active zeolite-
containing catalysts requires an understanding of how the
crystal structure of zeolites changes in severe thermal and
hydrothermal conditions in the presence of matrices of
The matrices used to prepare modern zeolite-
containing catalysts are complex multicomponent
systems capable to satisfy a number of requirements
to catalysts in the course of their operation [1–4]. The
behavior of catalysts is determined both by properties of
separate constituents (zeolite and matrix components) and
by their mutual inﬂ uence. The presently used matrices are
of multicomponent nature because separate components
frequently fail to provide properties necessary for
One of ways to improve zeolite-containing systems
consist in using montmorillonite as a matrix component.
Montmorillonite has a high plasticity, which leads to
a good moldability of its mixtures with other components
of a catalyst. The high heat capacity of montmorillonite
favors heat release from the zeolite component in the
regeneration stage and thereby improves the thermal
stability of the catalyst [4–6].
The number of studies concerned with zeolite-
containing catalysts in matrices of various compositions
is sufﬁ ciently large [7–11], whereas information about
the effect of matrix components on the behavior of
zeolites in severe temperature conditions of processes is
comparatively scarce [12–14]. There have been reports
about the role of the amorphous matrix in hydrothermal
aging of cracking catalysts  and on the effect of Na-
montmorillonite on the acidity and catalytic properties
of zeolite-containing catalysts .
The aim of the present study was to determine how
matrices of various compositions affect the thermal
stability of zeolites Y and ZSM-5.
As starting components for fabrication of model
samples served zeolite Y in a mixed cation-decationized
form, zeolites ZSM-5 with SiO
ratios in the lattice
of 30 and 70, natural montmorillonite with SiO
ratios in the lattice of 30 and 70, natural montmorillonite
in the calcium form, silicon dioxide sol, amorphous
aluminosilicate, and reprecipitated aluminum hydroxide
with a pseudoboehmite structure.
All the catalyst samples were prepared by mixing
aqueous suspensions of components, with the subsequent
ﬁ ltration and molding of the mixture. The resulting
catalyst has grains with a nearly spherical shape, 0.25–