N-HEXANE REFORMING REACTIONS OVER BASIC PT-ETS-10 AND PT-ETAS-10

The dehydrocyclisation of n-hexane to benzene has long been reported t o be selectively catalysed by Pt-KL and other Pt impregnated basic zeo lites. In this contribution, Pt-impregnated basic microporous titanosi licates ETS-10 and ETAS-10 are shown to catalyse this reaction with re markably high selectivities. Although these two materials are topologi cally identical, their catalytic performance differs substantially. Pt -ETAS-10 is less active and less selective than Pt-ETS-10, whereas sel ectivities for benzene were found to increase considerably with temper ature for both catalysts. The selectivity difference between Pt-ETS-10 and Pt-ETAS-10 is more pronounced at higher reaction temperatures. Th e differing catalytic behaviour of these materials is suggested to rel ate to their chemical nature and may be explained on grounds of acidit y. Although ETS-10 and ETAS-10 materials exhibit the same acidity, Pt- ETAS-10 was found to be more acidic than Pt-ETS-10. The enhanced acidi ty of Pt-ETAS-10 is purported to be responsible for its low catalytic performance. (C) 1998 Academic Press.