MOFs衍生TiO_(2)负载硅钨酸的制备及催化合成生物柴油

Preparation of MOFs derived TiO_(2) supported silicotungstic acid and its catalytic synthesis of biodiesel

采用水热法制备了金属有机框架[MIL-125(Ti)]负载的硅钨酸(HSiW),以其作为前驱体,经煅烧后得到HSiW/TiO_(2)复合催化剂,通过X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)、扫描电镜(SEM)、透射电子显微镜(TEM)、N_(2)吸附脱附及NH_(3)-TPD等技术手段对催化剂的物理化学性能进行了表征,并用于催化油酸与甲醇的酯化反应,考察其催化活性及稳定性。结果表明,HSiW/TiO_(2)表现出高的催化活性,归因于催化剂具有多孔结构及高的酸性;当油酸与甲醇摩尔比为1∶20、催化剂用量为5%(以油酸质量为基准)、160℃条件下反应4 h,油酸的转化率达90.8%,且该催化剂经6次循环使用后转化率仍达70.6%。

Silicotungstic acid on metal-organic frameworks [MIL-125( Ti) ] had been synthesized as a precursor using a hydrothermal method,and subsequent calcination,the HSi W/TiO_(2) composite catalyst was obtained. The synthesized catalysts underwent X-ray diffraction( XRD),Fourier transform infrared spectroscopy( FTIR),scanning electron microscopy( SEM),transmission electron microscopy( TEM),N_(2)-adsorption-desorption and NH_(3)-TPD to identify its physicochemical properties. Moreover,the HSiW/TiO_(2) was used for the catalytic esterification of oleic acid with methanol,and the catalytic activity and stability of the catalyst was investigated. The results showed that HSiW/TiO_(2) showed high catalytic activity,which was attributed to the porous structure and high acidity of the catalyst;When the molar ratio of oleic acid to methanol was 1 ∶ 20,the amount of catalyst was 5 %( based on the mass of oleic acid) and the reaction was carried out at 160 ℃ for 4 hours,the conversion of oleic acid was 90. 8 %,and the conversion of the catalyst was still 70. 6 % after six cycles.