ZSM-5 — An active, selective and stable catalyst for skeletal isomerisation of n-butene Original Research Article

A series of H-ZSM-5 catalysts with a varying Si/Al ratio, varying particle size and varying substitution (Fe for Al) has been studied in skeletal isomerisation of n-butene in continuous flow experiments. The various H-ZSM-5 catalysts which, unlike the other 10-membered ring molecular sieves, show a very low selectivity at standard conditions, have been used under modified reaction conditions. After changes on the catalyst, and under optimised conditions ZSM-5 showed rather high selectivity and yield of isobutene. The just mentioned modifications were suggested on basis of the knowledge on the mechanism of skeletal isomerisation and of the accompanying side reactions.