稀土镧改性磷钨杂多酸盐催化油酸与甲醇酯化反应合成生物柴油活性研究

以H ₃PW ₁₂O ₄₀和La(NO ₃) ₃为原料，通过离子交换法制备一种稀土镧改性磷钨杂多酸盐催化剂.通过扫描电镜、红外光谱和X射线粉末衍射等表征方法，对合成的催化剂的物理及化学性能进行分析，进而通过以油酸和甲醇为反应物的酯化反应，对其催化活性进行研究.结果表明:稀土镧已经导入磷钨杂多酸的骨架结构，并与杂原子P形成配位键，有效提高磷钨杂多酸的比表面积和孔径；合成的催化剂具有完整的Keggin型结构；当反应温度为62 ℃，油酸与甲醇摩尔比为1∶6，反应时间为4.5 h，催化剂用量为反应物质量的2.5 %，油酸的转化率可达88.0 %. 

Catalytic activity of La-modified phosphotungstic heteropoly acid salt in synthesis of biodiesel from esterification of methanol and oleci acid

La-modified phosphotungstic heteropoly acid salt catalyst was prepared by using H3PW12O40 and La(NO3)3 as raw materials through the ion exchange method. The physical and chemical properties of the obtained-catalyst were analyzed with the employment of scanning electron microscopy, infrared spectroscopy and X-ray powder diffraction. The catalytic activity of the obtained-catalyst was studied in the esterification reaction with the oleic acid and methanol as raw materials. The results show that the rare earth lanthanum has been introduced into the skeleton structure of phosphotungstic heteropoly acid and formed new coordination bond with the heteroatom P, which effectively improved the specific surface area and pore size of phosphorus tungsten heteropoly acid; La-modified phosphotungstic heteropoly acid salt keeps the Keggin structure of phosphotungstic heteropoly acid completely. A yield of oleic acid methyl ester 88.0 % is obtained when the reaction temperature is 62 °C, the molar ratio of methanol and oleic acid is 1:6, reaction time is 4.5 h, and the mass ratio of catalyst to the reactants (oleic acid and methanol) is 2.5%.