PREPARATION OF PHOSPHOMOLYBDATES (TUNGSTA TES) BY SOLID-STATE REACTION AND BY PRECIPITATION - CATALYTIC BEHAVIOR IN PROPAN-2-OL CONVERSION

The method of preparation of heteropoly anions is a decisive factor fo r their catalytic behaviors. A possibility to prepare a catalyst by di fferent ways of synthesis, can help to understand the origin of its ac tivity. A new way to prepare 12-molybo(tungsto)phosphate salts of cesi um, rubidium and potassium, by solid state reaction, is evidenced. The se heteropoly salts were obtained anhydrous, they show a particularity to have a weak surface area (lower than 3 m(2)g(-1)) and no porosity. Porous salts with a similar crystallographic structure were prepared in aqueous solution. These different samples were tested in the reacti on of the propan-2-ol conversion in order to determine their catalytic acido-basic and redox behaviors. The catalytic results depend clearly on the way of synthesis.