Effect of titania phase composition in WO3/TiO2 catalysts on catalytic properties in dehydration of ethanol to diethyl ether

Abstract

At the present, several agricultural products can be used as raw materials for bio-ethanol production and consequently converted it into many valuable substances such as ethylene and diethyl ether. This can undergo via WO3/TiO2 catalyst in which the anatase phase of titania usually has a better activity on ethanol dehydration to diethyl ether and ethylene than rutile phase. However, pure anatase phase of titania perhaps does not give the best of catalytic properties. So, this study investigates on the effects of tungsten on titania-supported catalysts with different phase composition of titania consisting of anatase and rutile phase with various proportion (TiO2-R0, TiO2-R25, TiO2-R50, TiO2-R75 and TiO2-R100). The catalysts were characterized to determine physical properties and analyzed dynamic catalytic properties. It was found that the WO3/TiO2-R50 catalyst gave the highest ethylene (79.6% yield) at 350°C and DEE (9.0% yield) at 300 °C due to it contained the highest weak to strong acid site ratio. Thus, WO3/TiO2-R50 catalyst was selected to study the stability of the catalysts on ethanol dehydration reaction. It was found that the catalyst was stable to the ethanol dehydration reaction to ethylene within 2 hours, but is not stable to diethyl ether by long ethanol dehydration reaction time effects coke formation. It is a factor to decrease active site on surface area leading to lower catalytic activity.