二氧化硅负载硫酸铁催化剂上的酯化反应及其动力学研究

通过溶胶-凝胶法和浸渍法制备了二氧化硅负载的硫酸铁[Fe(2SO4)3/SiO2]催化剂,研究了[Fe(2SO4)3/SiO2]的焙烧温度、硫酸铁的负载量、催化剂用量及反应温度对油酸乙酯合成的影响。用积分法研究了等量反应物在常压下的反应动力学。结果表明,二氧化硅负载的硫酸铁催化剂在油酸和乙醇无溶剂条件下的酯化反应中具有良好的催化性能。酯化反应符合假设的朗格缪尔-欣谢尔伍德(L-H)机理,且服从准二级反应动力学方程,表观活化能为50.40kJ/mol,指前因子为1.22×10(7mol/L)-1·h-1。

KINETICS STUDY OF THE ESTERIFICATION ON SILICA-SUPPORTED FERRIC SULFATE CATALYST

The silica-supported ferric sulfate [Fe2(SO4)3/SiO2] catalysts were prepared by impregnating SiO2 in ferric sulfate aqueous solution followed by calcination in air at high temperature. The effects of calcination temperature, loading amount of ferric sulfate, the amount of catalyst used, reaction time and reaction temperature on the synthesis of ethyl oleate were investigated. Results showed that Fe2(SO4)3/SiO2 was an efficient solid catalyst for the esterification of oleic acid and ethanol under solvent-free condition. The kinetic study of the reaction was carried out by an integral method and using an equivalent proportion of the reactants under atmospheric pressure. It was also found that the experimental data were in good agreement with the reaction mechanism proposed by Langmuir-Hinshelwood model. The experimental data fitted the pseudo second-order rate equation. The apparent activation energy and the pre-exponential factor were calculated to be 50.40 kJ•mol−1 and 1.22×107(mol/L)-1•h-1, respectively.