Res. Chem. Intermed.
, Vol. 30, No. 3, pp. 337– 342 (2004)
Also available online - www.vsppub.com
Changes in surface composition of Fe-Si-Cr-K oxide
alkylation catalyst: the marked role of potassium ferrites
, ANDRZEJ KOTARBA
and ROMAN KLIMKIEWICZ
Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow, Poland
W. Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Science,
P. O. Box 1410, 50-950 Wrocaw 2, Poland
Received 26 November 2003; accepted 15 January 2004
Abstract—The in uence of gas-phase methylation of phenol on the state of the Fe-Si-Cr-K oxide
catalyst surface was investigated by thermodesorption of K atoms and ions. Changes in potassium
desorption energies, as determined from Arrhenius-like plots, varied from 3.07 eV to 1.21 eV for
the atoms and from 2.59 eV to 2.89 eV for ion desorption from the active and deactivated samples,
respectively. The results were discussed in terms of transformation of the catalyst surface and
formation of ¯-ferrite.
: Potassium desorption; catalytic alkylation; iron oxide catalyst.
Aromatic chemicals are mainly produced by means of traditional methods of or-
ganic synthesis. In these processes only a fraction of substrates is transferred into
desirable products, the rest being noxious waste. Additionally, highly dangerous
and toxic intermediates create an additional threat of environmental pollution. The
replacement of organic synthesis with a catalytic one  allows for clean and ef-
cient methods of production, e.g. such important compounds as methylphenols
(ortho-cresol and 2.6-xylenol) which are used as intermediates in many synthe-
ses [2, 3]. Alkyl derivatives of 1- and 2-naphthol are believed to be as interesting
as alkylphenols commonly used as the raw materials basis in the production of azo-
dyes, pigments, insecticides and drugs. However, the selective alkylation of naph-
thols is a dif cult task, since the aromatic ring, once alkylated, is more susceptible
To whom correspondence should be addressed. Fax: (48-12) 634-0515.