【摘要】 目的探索三聚磷酸铝替代硫酸催化合成阿司匹林的可行性。方法采用Benson基团贡献法、Joback基团贡献法,估算水杨酸与乙酸酐的反应体系的热力学函数,分析了该反应的焓变、熵变和吉布斯自由能随温度的变化,以及反应物酐酸摩尔比对平衡转化率的影响。结果在298.15 K~358.15 K的温度区间,该反应的焓变小于零,为放热反应,升温不利反应进行;在计算温度范围内提高反应的酐酸比,有利于增大平衡的转化率,当酐酸比为3时,理论转化率可达99.58%。结论从热力学角度考虑该催化合成反应是可行的。更多还原

【Abstract】 Objective To explore the feasibility using aluminum tripolyphosphate as the synthesis of aspirin model instead of sulfuric acid catalyst.Methods The thermodynamic functions of the reaction system of salicylic acid and acetic anhydride were calculated according to the Benson group contribution method and Joback group contribution method.The enthalpy change,entropy and Gibbs free energy along with the change of temperature as well as the influence of the molar rate of reactants on the equilibrium conversation rate were also studied.Results In the temperature range of 298.15 K to 358.15 K,the reaction enthalpy was less than zero,and was exothermic reaction,and increase of temperature was not conducive to the reaction.The improvement of mole ratio of salicylic acid and acetic anhydride was helpful to improve the equilibrium conversation rate.The theoretical conversion rate could reach 99.58% when the mole ratio of salicylic acid and acetic anhydride was 3.Conclusion From the viewpoint of thermodynamics,the reaction is practical and feasible.更多还原