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YUFEROVA et al.
can exhibit a certain synergism and can even exhibit new
properties that are not simply a sum of the properties of
the starting components.
dried until the optimal molding moisture content was
reached. The materials obtained were molded with a
manual extrusion device of piston type with channel
diameter of 1.5 mm and dried for 12 h at room temperature
and then for 3 h at a temperature of 110°C, with the
subsequent calcination at 700°C.
The main problem consists in that only a little progress
in the development of heterogeneous alkylation catalysts
has been made during the recent years because all
these catalysts are rapidly deactivated and show a poor
selectivity with respect to the target products.
Zeolite of the H-Beta structural type was preliminarily
calcined at 300°C for 1 h and then a calculated amount
of zirconium dioxide was deposited by the full moisture
absorption method from an aqueous solution of ZrOCl2.
The resulting samples contained 4, 8, and 16 wt %
zirconium dioxide. After the samples were dried at a
temperature of 110°C for 3 h, zirconium oxychloride
was hydrolyzed in an excess amount of distilled water.
Ammonium hydroxide was added dropwise under
thorough agitation until the pH reached a value of 11.
Then the samples were filtered and washed with an excess
of twice-distilled water until Cl– anions disappeared
(controlled by AgNO3 test), with the subsequent drying
at 110°C for 3 g. The sulfation was performed by
impregnation by the incipient wetness impregnation
method with a sulfuric acid solution (8 wt % SO3 relative
to zirconium dioxide). The samples were dried at a
temperature of 80°C and calcined at 700°C.
The goal of our study was to examine the physico-
chemical characteristics of catalysts having the form of
sulfated zirconium dioxide supported by H-Beta zeolite
and their effect on the stability and activity in the target
reaction of isobutane alkylation with isobutylene.
EXPERIMENTAL
H-Beta zeolite with Si/Al = 25 was produced by the
method described in [5]. Pseudoboehmite of Pural SB
brand was used as a binder for catalysts. Zirconium
oxychloride (Sigma Aldrich) served as the precursor
of zirconium oxide. Sulfate zirconium hydroxide was
produced by the method described in [6]: 85 g of
concentrated sulfuric acid, 277 mL of deionized water,
and 970 g of zirconium oxychloride octahydrate were
mixed, and the mixture was cooled to 10°C. Further, a
10% solution of ammonium hydroxide was added under
permanent agitation to until pH 12–13 was reached. On
being formed, the precipitate was washed until no Cl–
and SO42– ions were found in washing water. On being
washed, the precipitate was repeatedly humidified to a
moisture content of about 50 wt % and then was subjected
to a hydrothermal treatment for 5 h under an excess
pressure of approximately 1.5 atm.After the hydrothermal
treatment, the precipitate was humidified with a twofold,
relative to its mass, amount of deionized water, and
concentrated sulfuric acid was added to the resulting
suspension (8 wt % SO42– ions relative to zirconium
oxide). After the acid was added, the suspension was
agitated 30 min and then dried at 100°C until the whole
amount of moisture was removed. After the drying, an
additional treatment with sulfuric acid (to additionally
introduce 6 wt % sulfo groups) was performed by the
method of incipient wetness inpregnation.
To examine the activity, the materials synthesized,
which contained zeolite and zirconium dioxide deposited
onto the zeolite in amounts of 4, 8, and 16 wt %, were
shaped together with Pural SB (Sasol) pseudoboehmite
as a binder into extrudates (25 wt % binder in the calcined
base). The extrudates were dried at 80°C and calcined at
700°C for 4 h. Prior to the catalytic tests, the catalysts
were ground, sieved to obtain a 0.5–1-mm fraction and
again calcined at 350°C for 1 h. All the samples are
described in Table 1.
The acid centers were quantitatively determined by
IR spectroscopy of adsorbed pyridine with a Shimadzu
IR Tracer-100 FT-IR spectrometer having an attached
vacuum gas cell [7]. Pyridine was desorbed at temperatures
of 150, 250, and 350°C. The molar extinction coefficients
for Lewis and Brønsted acid centers were taken from the
literature [8].
The phase compositions were examined by X-ray
diffraction (XRD) analysis on a Shimadzu XRD-7000
instrument with monochromatic CuKα radiation (λ =
0.154051 nm).
The molding compound was produced by mixing of
a twice sulfated zirconium hydroxide with a calculated
amount of pseudoboehmite in a 75 : 25 ratio (calculated
for calcined materials) in an excess amount of deionized
water. The suspensions were agitated for 1 h and then
The texture characteristics were determined with
a Quantachrome Autosorb-6 ISA specific surface
area analyzer. Nitrogen gas served as adsorbate, the
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 90 No. 10 2017
Yuferova
