Summary: The Effect of Y-zeolite Acidity on m-Xylene Transformation Reactions
, A. Iliyas, A. Al-Amer, T. Inui
Department of Chemical Engineering, King Fahd University of Petroleum &
Minerals, Dhahran 31261, Saudi Arabia.
m-Xylene transformation has been studied on as-prepared H-Y and a series of dealuminated Y
zeolite catalysts. The conversion of m-xylene was found to increase initially with acidity, however,
decreases subsequently. It has been proposed that the high concentration of acid sites in the H-Y
catalyst increases paring reaction, in addition to the well-known isomerization and disproportionation
pathways. A significant decrease was observed with respect to disproportionation/paring (D/Pa) ratio
versus reaction temperature. This indicates that higher activation energy is required for paring as
compared to disproportionation reaction. The p-xylene/o-xylene (P/O) was established to be
independent of zeolite acidity. A higher coke deposition was found for the transformation of m-xylene
over the parent H-Y as compared to the highly dealuminated USY zeolite. The formation of benzene
and C2 - C4 gases were found to be proportional to zeolite acid concentration.
Keywords: m-Xylene transformation, Y zeolite, isomerization, disproportionation, paring reaction.
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