Effects of titania phase and tungsten loading content in W/TIO2 catalysts on dehydration of ethanol to diethyl ether

Abstract

Nowadays, ethanol which is one of the most used renewable energies can be converted into the more valuable compounds. It was reported that titania-supported tungsten (W/TiO2) catalyst is able to convert ethanol into diethyl ether. However, titania support has different crystalline phases that can result in differences of physicochemical properties for the catalyst. Therefore, the present work reports on the catalytic behaviors of both different phases of titania and tungsten loading contents in catalytic ethanol dehydration to diethyl ether. To prepare the catalysts, the three different phases [anatase (A), rutile (R), and mixed phases (P25)] of titania supports were impregnated with 10 wt% of tungsten and denoted as 10W/TiO2-A, 10W/TiO2-R, and 10W/TiO2-P25, respectively. Moreover, ethanol dehydration was also performed to determine the overall activities for all catalysts. It was found that the 10W/TiO2-P25 catalyst exhibits the highest DEE yield (24.1%) at 300°C and ethylene yield (60.3%) at 400°C, whereas only 15.9% is obtained from 10W/TiO2-R catalyst. Besides the different phases of titania support, higher surface area of TiO2 is likely to play an important role on the better dispersion of acid sites leading to higher catalytic activity. Moreover, TiO2-P25 support was selected to further study to investigate the effect of W loading (0-20 wt%), which was denoted as 5W/TiO2-P25, 10W/TiO2-P25, 15W/TiO2-P25 and 20W/TiO2-P25, respectively. It was found that the 15W/TiO2-P25 catalyst gives the highest activity with DEE of 30.4% yield at 300°C and ethylene of 65.8% yield at 400°C due to its three major roles including; (1) high surface area, (2) high amount of W species distributed on the external surface of catalyst and (3) introduce acid sites as active sites in the reaction. There were the factors leading to obtain higher activity for ethanol dehydration of 15W/TiO2-P25 catalyst.