Abstract:
A series of mixed TiO
2-ZrO
2 oxide catalysts used for the dehydration of octadecanol to octadecene were prepared by doping TiO
2 in ZrO
2 and calcining at 350-500 ℃. With the increase of calcination temperature, the amount of Lewis acid sites on the catalyst surface gradually increases. The amount of Lewis acid sites on the catalyst calcined at 450 ℃ is the most, and when the calcination temperature is over 450 ℃, the amount of Lewis acid sites decreases. No Brønsted acid sites are found on the catalysts. The mixed TiO
2-ZrO
2 oxides calcined at temperature below 400 ℃ contain Ti-O-Zr bonds and amorphous structure. The mixed TiO
2-ZrO
2 oxides with calcination temperature above 400 ℃ show monoclinic and tetragonal phases of ZrO
2. The crystalline phase of the metal oxides and amount of the acid sites simultaneously affect the performance of the catalysts. The acid sites on the mixed TiO
2-ZrO
2 oxides with amorphous structure have much higher dehydration activity than those with monoclinic and tetragonal zirconia crystalline phases. The catalyst calcined at 400 ℃ has the highest yield of 1-octadecene.