CONVERSION OF HEAVY N-ALKANES INTO LIGHT ISOMERS OVER H-MORDENITE, PLATINUM H-MORDENITE, PLATINUM/ALUMINA AND COMPOSITE CATALYSTS/

H-MOR, chlorided Al2O3, Pt/H-MOR, Pt/Al2O3, Pt-Re/Al2O3 and some of th eir mixtures were used as catalysts in the isomerization-cracking of p ure n-alkanes (n-C-7 to n-C-12) and two paraffinic commercial cuts at 1.5 MPa, 473-773 K, H-2:n-alkane=6 and weight hourly space velocity=4. Depending on the degree of conversion, the sequence of reactions on a ll catalysts was: isomerization, central and successive cracking. The activity and selectivity to light isomers increase with the increase i n platinum concentration using Pt/H-MOR. The conversion increases with the chain length of the n-alkane, presenting an optimum temperature a t which light isomers production is maximum. Ratios isoalkane/n-alkane higher than those corresponding to thermodynamic equilibrium are obta ined. H-MOR is deactivated due to the production of a large amount of coke, which greatly decreases the specific surface area and pore volum e of the zeolite. The synergy produced by the addition of platinum dec reases deactivation and increases the selectivity to isoalkanes. A com posite catalyst obtained by pressing powders of H-MOR and Pt/Al2O3 (pl atinum is in this case outside the zeolite particle) showed the best s ynergetic effect, which depends on the contact of the particles and wh ich is ascribed to hydrogen spillover from platinum to H-MOR. This spi llover decreases coke formation on and blocking of the surface of H-MO R.