Preparation of fluorinated-desilicated ZSM-5 zeolites with high surface acidity properties

The combination of two modification techniques developed for the ZSM-5 zeolite, i.e., desilication and incorporation of fluorine/thermal treatment, has produced a highly efficient catalyst for the synthesis of methyl tert-butyl ether (MTBE). The total acid density and the strength of some acid sites increase significantly with this sequential preparation procedure. In fact, with respect to the parent zeolite, the acid density increases by almost 80% and some stronger acid sites are formed. The yield of MTBE is comparable to that formed with the commercial catalyst, Amberlyst 15. However, with the new inorganic catalyst, no bulky by-products are formed owing to the shape selectivity of the ZSM-5 zeolite structure. (C) 2000 Elsevier Science B.V. All rights reserved.