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.