ISSN 1070-4272, Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 3, pp. 512–514. © Pleiades Publishing, Ltd., 2009.
Original Russian Text © S.I. Aliev, E.I. Akhmedov, E.S. Mamedov, T.O. Gakhramanov, 2009, published in Zhurnal Prikladnoi Khimii, 2009, Vol. 82, No. 3,
pp. 518–520.
BRIEF
COMMUNICATIONS
Effect of Phosphorus Content on Physicochemical
and Catalytic Properties of H-Ultrasil
in the Reaction of Toluene Ethylation
S. I. Aliev, E. I. Akhmedov, E. S. Mamedov, and T. O. Gakhramanov
Baku State University, Azerbaidzan
Received July 29, 2008
Abstract―Physicochemical properties of H-ultrasil modified with phosphorus and effect of the modification
on the toluene alkylation with ethanol were studied.
DOI: 10.1134/S1070427209030318
A promising method of producing p-ethyltoluene
(p-EtTol), a valuable compound for the synthesis of p-
methylstyrene, is ethylation of toluene on zeolites with
high content of silica of ZSM-5 type. A possible route
to modification of catalytic and molecular sieve
properties of zeolites is porosity control and
modification of acidic centers by removing the
strongest ones and changing their nature. Promising is
the chemical modification of zeolite using compounds
of B, Mg, P, Si and others [1–5] that increase para-
orientation activity of the zeolite based catalysts at the
transformations of aromatic hydrocarbons.
then for 4 h in a drier at 110°C, and then they were
calcinated in a muffle furnace for 4 h at 550°C. For the
investigation of the catalysts obtained were used
chemical, X-ray phase and adsorption methods of
analysis. Acid properties of the modified zeolites were
investigated by the method of ammonia thermo-
desorption along the procedure described in [2, 3]. For
the experiments was used a flow-type setup with the
4 cm3 by volume of catalyst as stationary phase in an
ideal replacement reactor at atmospheric pressure in
the presence of hydrogen in the temperature range
300–400°C with feeding of 1 h–1 volume rate and mole
ratio C7H8:C2H5OH:H2=2:1:2. Analysis of the reaction
products was carried out by means of chromatography
[3].
In this work we studied effect of modification of H-
ultrasil with ammonium hydrophosphate on its physico-
chemical and catalytic properties in connection with
the reaction of toluene ethylation.
Table 1 lists the data on activity and selectivity of
H-ultrasil in the reaction of toluene ethylation. The
reaction temperature did not affect the ethanol
conversion that remained on the level 92–100%, the
toluene conversion raised with temperature from 24.5
to 39.3 wt %. A long side toluene and EtTol in the
hydrocarbon fraction of the catalyzate were detected
aliphatic hydrocarbons C≥5, benzene, ethylbenzene,
xylenes ant other aromatic hydrocarbons. In gaseous
products were detected saturated and unsaturated
hydrocarbons (C1–C4). At lower temperature the
process was complicated with formation of aliphatic
hydrocarbons C≥5, at higher temperature by the
EXPERIMENTAL
For the study was used a zeolite of ultrasil type
with the mole ratio SiO2/Al2O3 = 61 that by means of
ion exchange was transformed to NH4-form along the
earlier described procedure [3]. The H-form of the
zeolite was prepared by thermal decomposition of the
NH4-form at 500°C for 4 h. The catalysts modified by
introduction of 0.5–4.0 wt% of phosphorus were
prepared by impregnating the zeolite H-form with a
solution of ammonium hydrophosphate at 80°C for
6 h. The samples obtained were dried in air for 16 h
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