HYDROISOMERIZATION AND HYDROCRACKING OF N-HEXANE ON PT SAPO-5 AND PT/SAPO-11 CATALYSTS/

The activity, stability, and selectivity of a series of bifunctional P t/SAPO-5 and Pt/SAPO-11 catalysts containing 0.5 wt% platinum, were co mpared for n-hexane transformation at 300-425 degrees C and atmospheri c, 3- and 5-bar hydrogen pressures. Hydrogen pressure had a strong inf luence on the activity, isohexane selectivity, and time-on-stream deac tivation. Isomerization to isohexanes was the major reaction in both c ases. However, Pt/SAPO-5 shows high activity and higher isohexane sele ctivity than Pt/SAPO-11 catalyst. The selectivity patterns found in th is class of molecular sieve catalysts are well interpreted in terms of a series of reaction pathways incorporating both confinement effects and shape selectivity factors as being important in determining the ob served product distribution.