Abstract: The structures of the reactants and products of synthesis of 4-Nitrophenylarsonic acid were studied by using the B3LYP method of density functional theory. Then the structures were optimized by computational analysis. The changes in reaction enthalpy, Gibbs free energy and equilibrium constant for the primary and side reaction were calculated and analyzed with the basic thermodynamic data obtained from vibration frequency analysis. The simulation results show that the primary reaction process is exothermic and irreversible, the enthalpy change is -15.0KJ/mol, the Gibbs free energy change is 39.7KJ/mol. The side reaction process is endothermic and irreversible, the enthalpy change is 10.0KJ/mol, the Gibbs free energy change is 45.2KJ/mol. The computational studies on thermodynamics of 4-Nitrophenylarsonic acid synthesis can provide the theoretical guidance to the reaction process condition control.

Key words: 4-Nitrophenylarsonic acid, computational simulation, density functional theory, thermodynamics

摘要： 采用密度泛函理论中的B3LYP方法，通过计算机模拟，研究了4-硝基苯胂酸合成反应中各物质的结构。在此基础上对反应热力学进行了模拟计算，通过计算，优化了反应物与产物的几何构型与电子分布，并得到了4-硝基苯胂酸合成反应的主副反应焓变、吉布斯自由能变以及反应平衡常数。模拟计算结果表明，主反应的焓变为-15.0KJ/mol，为放热反应，副反应的焓变为10.0KJ/mol，为吸热反应，主反应的标准吉布斯自由能变为39.7KJ/mol，而副反应的吉布斯自由能为45.2KJ/mol，该反应为不可逆反应。4-硝基苯胂酸合成反应的热力学性质的计算为反应工艺条件的控制和热力学研究提供了理论指导。

关键词: 4-硝基苯胂酸, 计算机模拟, 密度泛函理论, 热力学