Synthesis and characterization of two novel large-pore crystalline vanadosilicates

Two novel large-pore sodium vanadosilicates (Aveiro-Manchester, structure numbers 13 and 14) containing stoichiometric amounts of vanadium (Si/V = 10 and 4, respectively) have been synthesized. Only one other example of a large-pore vanadosilicate (AM-6) is known. AM-13 and AM-14 were characterized by bulk chemical analysis (ICP); powder X-ray diffraction (XRD); scanning electron microscopy (SEM); thermogravimetric analysis (TGA); differential scanning calorimetry (DSC); N-2, n-hexane, benzene, and tripropylamine adsorption measurements; and Raman and diffuse reflectance ultraviolet-visible (DR UV-vis) spectroscopies. The acid-base and redox properties of these materials were assessed by 2-propanol conversion and ethanol oxidation, respectively. Both materials exhibit high selectivities to acetaldehyde, indicating that these two novel vanadosilicates are promising redox catalysts.:However, because the thermal stability of AM-14 is modest (ca. 350 degreesC), its potential use as a catalyst is limited.