Investigation of the Synthesis of Zeolitic Vanadotungstate and its Use in the Separation of Propylene/Propane at High Temperature and Humidity.

Synthetic conditions for the zeolitic octahedral metal oxide based on vanadotungstate are studied. The temperature, time, acidity, W/V ratio, cation species, and concentration affect the resulting materials. The study shows that mixing tungstate and VO2+ in an aqueous solution generates cubane units ([W4O16]8-) at room temperature. The cubane units assemble with VO2+ immediately to form a solid with an amorphous phase and nonporosity, which further crystallizes under a hydrothermal condition to form the crystalline microporous vanadotungstate. The zeolitic vanadotungstates act as effective adsorbents for the separation of propylene/propane. The active materials effectively separate propylene/propane even at high temperatures and high humidities.