A. Germain et al., VAPOR-PHASE NITRATION OF FLUOROBENZENE WITH N2O4 OVER ALUMINOSILICATES - EFFECTS OF STRUCTURE AND ACIDITY OF THE CATALYST, Applied catalysis. A, General, 136(1), 1996, pp. 57-68
The vapour-phase nitration of fluorobenzene with dinitrogen tetroxide
has been investigated over amorphous silica-alumina and zeolites with
various structures and aluminium contents. The activity of the catalys
ts increases with the number and the strength of the acid sites, but i
s also very dependent on the accessibility controlled by the pore stru
cture and the size of the crystals. Except, the zeolite BEA which is t
he most active and the most stable, the deactivation of the catalysts
is fast since the activity is high. The addition of water to the feed
increases the activity and the stability of all the zeolites, but decr
eases the activity of amorphous silica-alumina. A large part of deacti
vation is attributed to the marginal formation of 2,4-dinitrofluoroben
zene which stays on the surface of the catalyst, but can be eliminated
by 'steam distillation'. No evidence of shape selectivity was obtaine
d. Zeolite BEA proved to be a remarkably efficient catalyst.