Preparation of Pd/TiO₂ catalyst using room temperature ionic liquids for aerobic benzyl alcohol oxidation

Pd/TiO₂ catalysts for aerobic benzyl alcohol oxidation were synthesized and eight different room temperature ionic liquids were used to control the palladium properties as active sites. Pd/TiO₂ particles were also calcined at 300, 400 and 500 ℃ to obtain an optimum catalyst. As the calcination temperature increased, the surface area and pore volume of catalyst decreased, but negligible changes were observed for the pore size of catalyst. However, the structural properties of catalyst varied with respect to the type of ionic liquids. Under identical reaction conditions, different catalytic activities were obtained depending upon the calcination temperature and type of ionic liquids. Mostly, the catalyst calcined at 400 ℃ showed higher catalytic activity than those at other temperatures. However, the catalyst prepared with 1-octyl-3-methylimidazolium hexafluorophosphate and 1-octyl-3-methylimidazolium trifluoromethanesulfonate showed good catalytic performance after calcination at 300 ℃. Among the catalyst, Pd/TiO2 prepared with 1-octyl-3-methylimidazolium tetrafluoroborate and calcined at 400 ℃ showed the highest catalytic activity.