1070-4272/04/7709-1500C2004 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 77, No. 9, 2004, pp. 1500!1504. Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 9,
2004, pp. 1510!1515.
Original Russian Text Copyright + 2004 by Egiazarov, Radkevich, Kravchuk, Ivko.
Thermal Stability and Activity in Hydrogen Oxidation
of Palladium Catalysts Supported on Fibrous Sulfonic Cation
Exchanger in the Hydrogen and Magnesium Forms
Yu. G. Egiazarov, V. Z. Radkevich, L. S. Kravchuk, and A. A. Ivko
Institute of Physical Organic Chemistry, Belarussian National Academy of Science, Minsk, Belarus
Received August 6, 2003; in final form, May 2004
Abstract-The effect of reduced palladium on the thermal stability of the hydrogen and magnesium forms of
FIBAN K-1 fibrous sulfonic cation exchanger was studied. The activity of palladium catalyst supported
by the H and Mg forms of the cation exchanger in hydrogen oxidation was determined, as influenced by
the temperature of treatment of the catalyst with the reaction mixture.
As shown previously , the thermal stability of
sulfonic cation exchangers in the metal forms is higher
than that of the H forms. In particular, a mass-spec-
trometric study (10
torr) of the physicochemical
properties of FIBAN K-1 sulfonic cation exchanger in
the alkali metal and alkaline-earth metal forms showed
that the Mg form had the highest thermal stability
[4, 5]. Hence, the Mg form can be used as a support
for metal catalysts of redox reactions.
However, the effects exerted by the metal phase on
the thermal stability of sulfonic cation exchanger and
by the metal cation on the catalytic activity of the
supported metal were not understood. In this work we
studied the thermal stability of the H and Mg forms of
FIBAN K-1 sulfonic cation exchanger containing
reduced palladium, the palladium dispersity in these
matrices as influenced by the exchangable cation, and
the palladium activity in hydrogen reduction as in-
fluenced by the temperature of the treatment of the
catalysts with the reaction mixture.
The H form of FIBAN K-1 fibrous sulfonic cation
exchanger was prepared by bulk radiation grafting of
styrene (98%)3divinylbenzene (2%) copolymer to
polypropylene staple fiber, followed by sulfonation of
the poly(styrene3divinylbenzene) matrix with concen-
Pure Mg form was prepared by washing of a
column packed with the H form (exchange capacity
3 mg-equiv g
) with excess 0.5 M MgCl
until pH of the solution at the outlet became neutral.
Then the column was washed with distilled water
until the absence of chloride ions in the wash waters
and then was dried in air.
To prepare catalysts with 2.5 wt % Pd content, the
H or Mg form of the cation exchanger was treated
under static conditions with a solution of tetrammine-
palladium(II) chloride [Pd(NH
of a definite
concentration at room temperature and pH 838.5.
The Pd(II) concentration in the solutions before and
after ion exchange was measured spectrophotometric-
ally . Then the samples were washed with distilled
water until the absence of chloride anions in the wash
waters, and the [Pd(NH
cations were reduced
with an aqueous solution of N
30 min. After that, the samples were washed again
with distilled water to neutral reaction and were dried
at room temperature.
To determine the degree of Pd(II) reduction, the
ion-exchangeable Pd(II) species were completely
washed out from the samples with excess 1 M NaCl
and then the palladium concentration in the solution
was measured. In the course of reduction, the ion-
exchange sites of the catalyst are converted to the
H form after removal of [Pd(NH
convert these sites into the Mg
form, the reduced
samples were repeatedly treated with a MgCl
tion, washed, and dried.
X-ray phase analysis of the palladium catalysts was
performed on a DRON-1 diffractometer using CuK
radiation. Thermal gravimetric analysis of the supports
and catalysts was performed on an MOM deriva-
tograph (Hungary) in the temperature range 203
The mass spectra of the gaseous thermolysis prod-
ucts of the samples were recorded on an MKh 1320