This study explores several microporous materials to identify the most
suitable structures for a skeletal isomerisation of n-butene to isobu
tene. The 8-membered ring zeolites are not suitable for skeletal isome
risation of n-butene to isobutene because their pore diameter does not
allow diffusion of isobutene. The 12-membered ring zeolites do not su
ppress the formation of carbonaceous deposits and their pores are quic
kly blocked. The most suitable materials are the catalysts with a pore
diameter between 4 and 5.5 Angstrom. This is the range as met in the
10-membered ring molecular sieves. These materials allow an isobutene
diffusion but they suppress the formation of dimers (and oligomers) wh
ich are intermediates leading to by-products. (C) 1997 Academic Press.