CHARACTERIZATION AND CATALYTIC EVALUATION OF SAPO-5 SYNTHESIZED IN AQUEOUS AND 2-LIQUID PHASE MEDIUM IN PRESENCE OF A CATIONIC SURFACTANT

High silica content SAPO-5 was synthesized using aqueous and two-liqui d phase systems in presence of hexadecyltrimethylammonium bromide. The scope of the work was to study the effect of the synthesis parameters on the amount of silicon incorporated into the network, the different silicon environments and on the catalytic activity in the m-xylene is omerization. The results showed that the use of the two-liquid phase s ynthesis causes greater incorporation and diversification of the silic on distribution in the SAPO-5 network and therefore, a substantial inc rease in the material acidity. The maximum catalytic activity in the c onversion of meta-xylene was achieved by the samples synthesized via t he two-liquid phase method and in the presence of the surfactant with 10 wt% of SiO2. Silica incorporation above 10% creates greater silicon domains, reducing drastically the catalytic activity of the material. (C) 1998 Academic Press.