Enhancement of Ion Exchange in a FAU Type Zeolite during the Synthesis of an Active and Selective Catalyst for Isobutane Alkylation with Butylenes

Resumo

The effect of ultrasonication on the efficiency of ion exchange in a binder-free pelleted NaX zeolite (the molar ratio Si/Al = 1.34) has been studied using successive treatments with calcium, lanthanum, and ammonium nitrate solutions at 80°C with intermediate calcining after each ion exchange step in comparison with the ion exchange performed under identical conditions without sonication. It has been found that the ultrasonic treatment (a current of 2.6 A) at 80°C in a solution makes it possible to achieve a deep exchange of sodium cations in the zeolite framework (less than 0.3 wt % residual sodium oxide). The comparison of the physicochemical and catalytic properties of the catalyst samples obtained of shows a substantial advantage of the method of ultrasound-assisted ion exchange due to the almost complete exchange of sodium for the multicharged cations.