介孔WO_3-CeO_2-ZrO_2固体超强酸的制备与催化性能

Preparation and Catalytic Activity of Mesoporous WO_3-CeO_2-ZrO_2 Solid Superacid Catalyst

以十六烷基三甲基溴化铵(CTAB)为模板,采用水热法合成了具有介孔结构的WO_3-Ce O_2-Zr O_2(WCZ)固体超强酸。研究了Ce掺杂量、WO_3含量、煅烧温度等因素对催化剂结构和酸性能的影响,以乙酸正丁酯的合成反应为探针,对介孔WCZ固体超强酸的活性进行了测试。结果表明:掺杂适量Ce有助于维持四方相Zr O_2的稳定,引入活性组分WO_3能有效提升催化剂的稳定性。当Ce含量为5%(摩尔分数),WO_3含量为20%(质量分数),经650℃煅烧后,介孔WCZ固体超强酸的比表面积为176.1 m^2/g,平均孔径为3.70 nm,孔体积为0.20 cm^3/g,乙酸转化率达到97.28%,使用4次后其乙酸转化率还能达到96.08%。

The mesoporous WO3-CeO2-ZrO2 solid superacid catalystwas synthesized by a hydrothermal method with hexadecyl trimethyl ammonium bromide （CTAB） as a template. The effects of Ce doping amount, WO3content and calcination temperature on the structure and acid properties of the catalysts were investigated. The catalyst activity was analyzedvia the esterification of acetic acid with n-butanol as a probe reaction. The results indicate that the tetragonal ZrO2 is stabilized at an appropriate doping amount of Ce. The stability of catalyst is improved effectively by introducing WO3 as an active component. The acetic acid conversion ratio, specific surface area, average pore size and pore volume of the catalyst with 20 % （in mass fraction） of WO3, 5% （mole fraction） of Ce calcined at 650℃ are 97.28%, 176.1m^2/g, 3.70nm and 0.20cm^3/g, respectively. Its acetic acid conversion ratio is 96.08% after used for four times.