1070-4272/05/7802-0273 + 2005 Pleiades Publishing, Inc.
Russian Journal of Applied Chemistry, Vol. 78, No. 2, 2005, pp. 273!277. Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 2, 2005,
Original Russian Text Copyright + 2005 by Zakarina, Volkova, Shchukina, Khan.
Pillared Tagan Montmorrilonite in Cracking
N. A. Zakarina, L. D. Volkova, O. V. Shchukina, and Ch. G. Khan
Institute of Organic Catalysis and Electrochemistry, Ministry of Education
and Science of the Republic of Kazakhstan, Almaty, Kazakhstan
Received September 10, 2004
Abstract-Tagan montmorillonite clay fixed with aluminum and zirconium oxides was prepared, and its
catalytic (in cracking of isopropylbenzene), adsorption, and structural characteristics were studied.
It is known that the heat resistance of catalysts de-
rived from clays is poor [1!4] because of the possible
closure of the silicate layers at high temperatures. In-
tercalation of metal oxide clusters (pillars) into the in-
terlayer space of montmorrilonite-type layered clays
by cation exchange with inorganic polyoxo cations al-
lows preparation of a new class of materials exhibit-
ing the prescribed porosity, acidity, and heat resistance.
Pillared clays attract researchers’ attention as adsorb-
ents and catalysts for cracking, isomerization, etc.
Preparation and use of intercalated clays have been
discussed in numerous reviews [1!3]. The features of
intercalation are specific to montmorillonites from
In this study, we examined intercalation of natural
Kazakhstan montmorrilonite from the Tagan deposit
and tested pillared materials derived from it in crack-
ing of hydrocarbons.
Montmorrilonite clay from the Tagan deposit was
used without isolation of the monomineral montmo-
rillonite fraction. The initial clay was converted to
the Na form by treatment with 1 M NaCl to raise its
dispersity. The H form of Tagan montmorillonite was
prepared by the standard procedure .
As fixing agents we tested oligomeric alumi-
num hydroxo cations of the presumed composition
) with a four-coordi-
nate Al atom, which were prepared according to  at
various synthesis temperatures, and aqueous solutions
, which were introduced into clay according
to . As reported in [7, 8], 70!80% of aluminum
hydroxo cations have a Keggin structure. Oligomeric
is commonly prepared by hydrolysis of a 0.2 M
solution in 0.5 M NaOH at OH
and final pH 4.1 with vigorous stirring. After aging
for 24 h, the fixing agent (oligomeric Al
) was added
dropwise into a 5% aqueous suspension of the clay.
The oligomeric complex was prepared at room tem-
perature  and at 353 K .
In the synthesized samples, the Al
/clay ratio was
2.5, 5.0, and 7.5 mmol g
clay. The resulting prod-
uct, aluminum!fixed montmorillonite (Al!FM), was
separated by centrifugation, washed to negative reac-
tion for Cl
ions, dried in a thin layer at 293 and
423 K, and calcined at 823 K.
Zirconium!fixed montmorrilonite (Zr!FM) was
prepared by slow addition of a ZrOCl
a given concentration to a 5% clay suspension. The ac-
tivity of the resulting samples was studied in a micro-
pulse installation in cracking of a model hydrocar-
bon, isopropylbenzene (IPB), in the temperature range
623!773 K (T
). The catalysts were preliminarily
calcined at 823 and 1023 K (T
). An X-ray diffraction
analysis was performed with a DRON-4.7 diffractom-
radiation). An electron-microscopic exam-
ination was performed with an EM-125K electron
microscope using microdiffraction. The specific sur-
face area, total pore volume, and pore size distribution
were determined with an ACCUSORB device from
the isotherms of low-temperature nitrogen adsorp-
The structural (first basal reflection in the diffrac-
tion patterns, d
, and interlayer spacing ,d) and ad-
sorption (pore volume V and specific surface area S
determined from by BET low-temperature N
tion) characteristics of the samples are listed in Table 1,
and the pore size distribution is shown in Fig. 1.