The deactivation and the selectivity of o-xylene isomerization reaction have been studied on silica-alumina, faujasite-Y and mordenite catalysts. Improving of catalytic stability has been attempted by using two types of treatment; wet air treatment, transition metal loading by ion exchange.
Wet air treatment and/or transition metal loading reduced the dactivation rate, but did not change the initial activities on o-xylene isomerization reaction of H-mordenite catalyst. Especially wet air treatment and/or transition metal loading of mordenite catalysts improved the isomerization selectivity.
As the deactivation proceeded, the isomerization selectivity was increased on zeolite catalysts. The selectivity of faujasite-Y catalysts is concave to total conversion axis, whereas the selectivity of mordenite catalysts is convex to total conversion axis. On the other hand, the selectivity of silica-alumina showed constant values for total conversion.
The isomerization selectivity on cobalt loaded mordenite was higher about 100 times as much as that on faujasite-Y type catalysts at total conversion of about 30 %.