A Study of The Properties of Modified High-Silica Zeolites
in the Conversion of Methanol to n-Xylene
S. E. Mamedov and I. Sh. Gendzhalieva
Baku State University, Baku, Azerbajan
Received July 22, 2009
Abstract—Catalytic and physicochemical properties of high-silica zeolites modified by multiple charge cations
(Zn, Cd, Ba, La, Lu) in the conversion of methanol to n-xylene were studied.
ISSN 1070-4272, Russian Journal of Applied Chemistry, 2010, Vol. 83, No. 6, pp. 1099–1101. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © S.E. Mamedov, I.Sh. Gendzhalieva, 2010, published in Zhurnal Prikladnoi Khimii, 2010, Vol. 83, No. 6, pp. 1044–1046.
The catalytic conversion of methanol may proceed
in different directions, depending on the nature of the
catalyst and the conditions of the reactions. The factors
affecting the process of the hydrocarbon formation
from methanol are object of numerous studies, which
are generalized and criticized in a number of reviews
[1, 2]. Nonetheless, the possibility of selective
synthesis of n-xylene in the presence of modified high-
silica zeolites has not been studied yet.
We study, how the nature and concentration of the
modifier and the procedure of its introduction affect
the physicochemical and catalytic properties of high-
silica zeolites in the conversion of methanol to n-
The experiments were performed on a flow-type
setup with a stationary catalyst bed of 4 cm
an ideal-displacement reactor at atmospheric pressure
in the temperature range 300–450°С. The volumetric
flow rate of methanol was 2 h
and the time of the
experiments, 0.5 h.
For the study was used a high-silica zeolite of
ultrasil type with the mole ratio SiО
= 61 that
by means of ion exchange was transformed into
cationic forms by the procedure described in . The
catalysts modified by introduction of 1.0–10.0 wt % of
lanthanum were prepared by impregnating the Н-
ultrasil with a solution of lanthanum nitrate. The
samples obtained were dried in air and then in a drier
at 110°С. The Lа–Н ultrasil was prepared by following
calcinations of the samples in a muffle furnace for 4 h
The acid properties of zeolites were studied by the
method of ammonia thermodesorption  and their
adsorption properties, by the method described in .
As known, the conversion of methanol on zeolite-
containing catalysts proceeds by the scheme :
methanol > dimethyl ether > olefins > H
isoparaffins and aromatic hydrocarbons.
In the temperature range 350–400°С the degree of
the methanol conversion is 100% on both initial and
modified Na-zeolite. The main products of the
300 350 400 T, °C
Yield, wt %
Fig. 1. Influence of the nature of the exchange cation on
the yield В (wt%) by aromatic hydrocarbons (С
methanol conversion in the presence of ultrasils (v = 2 h
(Т) Temperature (°C). (1) Na-ultrasil; modifier content
(wt %): (2) 0.83 Ba, (3) 0.66 Zn, (4) 0.70 Cd, (5) 0.68 La,
(6) 0.71 Lu, and (7) 0.81.