低氢酯比条件下苯甲酸甲酯加氢制苯甲醛动力学

Kinetics of Hydrogenation of Methyl Benzoate to Benzaldehyde at Low Molar Ratio of H_2 to Ester

以4%Li3%Cr修饰的25%ZnO/MnO/βAl_2O_3为催化剂,采用固定床反应器,在消除内外扩散的情况下,考察了反应温度和氢酯比对苯甲酸甲酯(MB)加氢制备苯甲醛的影响,并建立苯甲酸甲酯加氢反应的本征动力学模型。以MB转化率和苯甲醛选择性的模型计算值与实验值的残差平方和最小为目标函数,采用Matlab软件中的非线性最小二乘法对实验数据进行拟合,估算出该模型的参数,并对模型的显著性进行了检验。结果表明,动力学模型具有合理性,能较好地描述苯甲酸甲酯加氢反应。

The effects of temeperature and molar ratio of H2 to methyl benzoate（MB） on hydrogenation of methyl benzoate were investigated in a fixed-bed reactor using 25 % ZnO/MnO/γ-Al2O3 modified by 4% Li 3%Cr as catalyst and eliminating the internal and external diffusion influence and the intrinsic kinetics model for hydrogenation of MB to benzaldehyde at low molar ratio of H2 to ester was built up. The minimum residual sum of squares of the model calculated and experimental values of MB conversion and benzaldehyde selectivity was used as the objective function. The parameters were obtianed by using nonlinear least-squares method of the Metlab software and the significance testing of the model was carried out. The results showed that the model for hydrogenation of methyl benzoate was resonable and could describle hydrogenation of methyl benzoate well.