ISOMORPHOUS SUBSTITUTION OF SILICON IN THE ALPO4 FRAMEWORK WITH AEL STRUCTURE - N-OCTANE HYDROCONVERSION

SAPO-11 solids were synthesized using either the classical or non-clas sical method (use of surfactant) and different crystal sizes were obta ined. Characterization was performed and it was observed that the soli ds have nearly the same number of acid sites but the acid strength is higher for SAPO-11 prepared with surfactant. Loaded with Pt-Pd, these solids were used in n-octane hydroconversion; both solids were highly selective for methyl-heptane formation, the activity of SAPO-11 with s mall crystals being the highest. These different catalytic behaviours are discussed in terms of 'pore mouth catalysis' and restricted transi tion-state selectivity. (C) 1998 Elsevier Science B.V. All rights rese rved.