硅钨杂多酸制备、表征及催化油酸酯化反应合成生物柴油活性研究

Studies on the preparation,characterization and catalytic activity test with oleic acid esterification of silicotungstic heteropoly acid

采用硝酸酸化-乙醚萃取法制备了一种硅钨杂多酸催化剂,应用扫描电镜(SEM)、红外光谱(FTIR)、X射线粉末衍射(XRD)、程序升温脱附(NH3-TPD)、热重分析(TG)等手段对催化剂进行了表征,并以甲醇和油酸为反应物,研究了所制备的硅钨杂多酸在催化酯化反应时的活性,考察了催化剂用量、反应时间、反应温度等反应参数对酯化反应产品收率的影响.结果表明:当甲醇与油酸的质量比为3∶2,催化剂用量为反应物总质量的1.4%,反应时间为3.5 h,反应温度为65℃时,油酸甲酯的收率最高,为96.45 wt%.

The nitric acid acidification method incorporated with an ether extraction technique is used to prepare a silicotungstic heteropoly acid catalyst in this study. The resulting catalyst is characterized by scanning electron microscopy （SEM）, infrared spectroscopy （FTIR）, powder X-ray diffraction （XRD）, temperature pro- grammed desorption of ammonia（NH3-TPD） and thermogravimetric analysis （TG）. The catalytic activity of the silicotungstic heteropoly acid catalyst is studied from the esterification reaction of oleic acid and methanol. The syntheses conditions with respect to catalytic activities have been optimized individually, including the mass ratio of methanol to oleic acid, as well as the mass ratio of catalyst to reactants, reaction time and reaction temperature. Results show that when the mass ratio of methanol to oleic acid is 3：2, mass ratio of catalyst to reactants is 1.4 %, reaction time 3.5 h and reaction temperature is 65 ℃, a yield of methyl oleate 96.45 wt% is obtained from this optimal reaction condition.