Fast tailoring of the acid–base properties in the NaX zeolite by cesium-exchange under microwave heating

NaX zeolite can show an acidic or basic behaviour depending on the degree of ion-exchange of sodium by cesium cations. The acid–base properties of the X zeolite are tunable by means of the cesium-exchange degree. This allows X zeolite to be prepared according to the needs of any determined reaction. Moreover, the cesium-exchange is carried out in a short period of time (5 min) when microwave radiation is used as the heat source. In addition, microwave heating decreases the volume of the ion-exchange solution. Only one cesium-exchange (28 cesium atoms per unit cell) under microwave heating was enough to annul the acid behaviour of the NaX zeolite in the toluene alkylation.