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 °C), its potential use as a catalyst is limited.