| Novel classes of bi-functional catalysts used in the conversion of n-paraffins, including various zeolites, lanthanum Y zeolites, desilicated zeolites, and sulfate-promoted hybridized zeolites have been prepared and characterized. The mechanisms and kinetic behaviours for n-paraffin (n-octane as a model) conversion over these catalysts have been thoroughly studied. The resulting information can be used for catalyst design and optimizing reaction conditions to favour a desired product distribution.;It has been shown that the cation-exchange capacity and acid density of a zeolite can be significantly improved by selectively removing some of its framework Si atoms with a basic solution under very precise conditions. However, these desilicated zeolites in the acid form are not as thermally stable as the parent zeolites. The presence of La is found to enhance such stability.;It has been confirmed that there exists a temperature window from 770 K to 870 K for optimum activation of sulfate-promoted zirconia used as a co-catalyst in a hybrid catalyst and a tetragonal crystalline structure for zirconia was obtained, without loss of sulfate groups and with subsequent good catalytic performance. Superacidic properties of the sulfate-promoted zirconia were characterized. The synergistic effect of the hybrid catalyst was credited to the transfer of reaction intermediates from the sulfate-promoted zirconia surface to the zeolite pore system.;Conversion of n-paraffins (C;Large amounts of isobutane and gasoline-grade isoparaffins are obtained over Pt-containing Y zeolite and hybridized catalysts at low reaction temperatures (... |
