Yg. Li et H. Jun, KINETICS STUDY OF THE ISOMERIZATION OF XYLENE ON ZSM-5 ZEOLITES - THEEFFECT OF THE MODIFICATION WITH MGO AND CAO, Applied catalysis. A, General, 142(1), 1996, pp. 123-137
Xylene isomerization over HZSM-5, MgO-HZSM-5, and CaO-HZSM-5 zeolites
has been studied using the pulse microreactor-chromatograph technique
and the dynamic modeling method. The rate constants, activation energi
es, and activation entropies for each step in the reaction network on
the catalysts have been obtained. These results indicate that strong a
cidity can favour the conversion of m- and o-xylene, while the isomeri
zation of p-xylene not only takes place on strong acidic sites, but al
so on the weaker acidic sites. The parameters also indicate that under
a loading amount of MgO or CaO in a mole ratio to framework aluminum
equal to 1:1, the influence of steric encumbrance caused by the introd
uction of MgO or CaO is less as compared with the changes of the surfa
ce acidity.