Hydroconversion Of Octylcyclohexane Over A Bifunctional Pt/Usy Zeolite Catalyst

Hydroisomerization and hydrocracking of octylcyclohexane (C14H28), obtained after in situ hydrogenation of the parent aromatic compound, phenyloctane (C14H22), on a Pt/Al2O3 precatalyst, were performed over a bifunctional Pt/USY zeolite catalyst, at 573 K, 6 MPa, and a molar ratio H-2/HC of 7 mol/mol. About 200 reaction products were identified and quantified with GCxGC-FID/MS and then lumped into families according to carbon number and chemical similarity. Insight into reaction pathways was gained from the evolution of the composition of the isomers and cracked products with conversion. The results illustrate a kinetic competition between isomerization steps, which increase the number of branchings on the ring by shifting carbon atoms from the long alkyl chain to the ring, with exo-cyclic cracking of the long alkyl chain. Favorable cracking distributions are reached as soon as the molecule is tribranched, which leads to a peak at C7 in the product distribution.