W USY ZEOLITES - INFLUENCE OF THE IMPREGN ATION ACIDITY IN THE STRUCTURAL-PROPERTIES AND THE CATALYSTS REDUCIBILITY/

Tungsten-modified ultrastable zeolite catalysts were prepared at three different pHs. Other reference solids were WO3 and a mechanical mixtu re of 20 wt% WO3 and 80 wt% USY. They were calcined and characterized by surface area measurements (S-BET), X-ray diffraction (XRD), acidity and temperature-programmed reduction (TPR). In the incorporation of t ungsten to the zeolite, the pH of the impregnation solution controls t he cristallinity, the surface area, the acidity of the zeolitic cataly sts, the size and the location of tungsten in the USY zeolite and the reducibility.