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Eyyub S. Mammadov, Nargiz F. Akhmedova, Sabit E. Mammadov, Ayten Z. Mamedova
Catalytic activity of Bimetallic
Rh-La/HZSM-5 catalysts in the methylation reaction of benzene
Abstract
Abstract. To solve the problem of annihilation of the MTO
(methanol-olefin) side reaction, increase the selectivity for xylenes,
especially p-xylene, and the stability of catalysts used in the benzene
methylation reaction, a two-component modification of HZSM-5 zeolite with
lanthanum and rhodium was carried out. The catalysts were characterized by XRD,
IR-Fourier, TPD-NH3, BET and BJH methods. Benzene methylation was
carried out in a flow reactor of ideal displacement at a temperature of 380 °C,
with a molar ratio of benzene:methanol equal to 1:1 in a hydrogen stream.
Bi-componently modification of HZSM-5 led to a decreasing in the density of
strong acid centers, to the formation of metal centers, to decreasing in pore
volume and an increase in the mezoporousness of the catalyst, which play a
major role in the annihilation of side reactions, increasing of p-xylene
selectivity and stability. The bimetallic Rh-La/HZSM-5 catalyst completely
annihilates the MTO side reaction and demonstrates the high selectivity (71.2%)
of p-xylene and stability (80 h).
Key words: benzene methylation, p-xylene, Rh-La/HZSM-5, catalyst
stability
Copyright (C) Chemistry Dept., Moscow State University, 2002
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