REACTION-MECHANISMS OF ISOMERIZATION AND CRACKING OF HEPTANE ON PD/H-BETA ZEOLITE

The vapor-phase isomerization and cracking of heptane on H-Beta zeolites loaded with various amounts of Pd metal has been studied at a temperature of 505 K and at a total pressure of 0.3 MPa. The cracking of heptane is interpreted as a combination of classic bifunctional hydrocracking and dimerization cracking. The isomerization of heptane proceeds through the classic bifunctional mechanism and a second mechanism involving dimerization cracking. The contribution of the different mechanisms to the isomerization and cracking is derived from the formation of specific reaction products. The contribution of the different mechanisms is dependent on the Pd content of the zeolite. (C) 1995 Academic Press, Inc.