A new way for obtaining acid or bifunctional catalysts. Straightforward calcination of as-synthesized [Ga]-ZSM-5 zeolites obtained from alkali-free media

Abstract

Straightforward calcination of as-synthesized alkali-free [Ga]-ZSM-5 zeolites leads to the formation of pure acidic or bifunctional gallium-promoted acidic MFI catalysts, depending upon the calcination temperature (Tc). At Tc≤530°C, the organic molecules are removed without any significant structural modification and zeolite behaves as a pure acidic catalyst. At Tc ≥ 700°C, this removal is accompanied by an important degalliation of the zeolite structure producing bifunctional catalysts (acid and Ga promoted) showing properties for propane and naphthene aromatization similar to those of the catalysts prepared by conventional impregnation method which involve relatively long and costly intermediate steps.