Synthesis And Catalytic Performance Of Sulfated Metal Oxides With High Specific Surface Area

As a kind of solid acids, sulfated metal oxides have drawn great attention due to their high catalytic activity in many organic reactions. At present, the preparation methods of sulfated metal oxides could be mainly classified into two types. The first one is precipitation followed by impregnation and another one is sol-gel. However, both of two methods used the liquid which polluted the environment, the operation process were complicated and cost a very long time. Meanwhile, sulfated metal oxides which were prepared by two methods have small specific surface area. Thus, the synthesis of sulfated metal oxides with high specific surface area by the convenient way has significant. In present study, solid phase synthesis, a new, non-pollution convenient preparation method, has been proposed to prepare sulfated titania and sulfated zirconia with high specific surface area.Firstly, sulfated titania preparing via the solvent-free method were researched. The influence about ratio of ammonium sulfate and titanium hydroxide, calcinations temperature were studied respectively. The ratio of ammonium sulfate and titanium hydroxide was 6:1, calcinations temperature was 550℃ had been considered the best synthesis conditions. Sulfated titania preparing under the best conditions had high specific surface area(107m2/g) which higher more than two times than the specific surface area of sulfated titania preparing via the conventional method. In the esterification reaction of acetic acid with benzyl alcohol, the percent conversion of benzyl alcohol was 91% on sulfated titania preparing via the solvent-free method. However, under the same reaction conditions, the percent conversion of benzyl alcohol was 37% on sulfated titania preparing via the conventional method.Then, sulfated zirconia preparing by the solvent-free method were researched. The influence about ratio of ammonium sulfate and zirconium hydroxide, calcinations temperature were studied respectively. The ratio of ammonium sulfate and zirconium hydroxide was 6:1, calcinations temperature was 600℃ had been considered the best synthesis conditions. The specific surface area of sulfated zirconia preparing under the best conditions of was 124m2/g, the specific surface area of sulfated zirconia preparing by the conventional method was 87m2/g. In the esterification reaction of acetic acid with benzyl alcohol, the percent conversion of benzyl alcohol was 81% on sulfated zirconia preparing by solvent-free method. However, the percent conversion of benzyl alcohol was 52% on sulfated zirconia preparing by the conventional method.Finally, both sulfated titania and sulfated zirconia with the high specific surface area could be prepared by solvent-free method and displayed high catalytic activity in the esterification reaction of acetic acid with benzyl alcohol. Further, solid phase synthesis could prepare sulfated metal oxides with high specific surface area and high catalytic activity.