【作者】 金文正；

【导师】 汪文川；

【作者基本信息】 北京化工大学 ， 化学工程， 1999， 博士

【摘要】 随着计算机技术的发展，计算机分子模拟已成为在分子水平上研究流体结构及性质的一种强有力工具，越来越受到化学工程界及其他一些领域的广泛重视。与传统的物性研究方法相比，计算机模拟方法有着独特的优越性。它可通过对模型流体的模拟，揭示宏观性质的微观本质，发现并解释实验现象和规律，指导建立流体的宏观性质模型；还可较严格地从分子的微观相互作用模型出发预测真实流体的宏观性质。在得到宏观性质的同时，还可获得实验无法得到的微观或介观结构图象，以利于分析现象和机理之间的内在联系。本文旨在利用计算机分子模拟方法预测无限稀释水溶液的性质，考察有机物在超临界水溶液中的亲水性以及多孔介质中流体吸附机理。 应用NPT系综MC方法考察BF，SPC，TIPS2，TIP3P，TIP4P等模型，确定了环境条件下最适宜的水分子间的相互作用势能模型TIP4P，以用于常温常压条件下无限稀释水溶液性质的模拟。以甲烷和苯为代表，分别采用NPT系综Monte Carlo耦合参数热力学积分法及分子蜕变耦合参数积分法模拟了无限稀释水溶液的亨利常数及活度系数。结果与文献模拟精度相当，说明本文计算无限稀释水溶液性质的方法具有一定的预测性。 以SPC模型为超临界水溶液水分子间的相互作用势能模型，苯作为有机物的代表，应用NVT系综MC方法，考察了超临界水的特殊微观结构，以及由此而引起的异常行为。通过考察温度、组成、密度等对苯的超临界水溶液中水及苯分子的微观结构的影响，并与常温下的纯水及纯苯溶液作比较分析，得出了有机物苯在超临界水中亲水的结论，并推荐了较适宜的与苯均相混合的超临界水条件，以用于指导化工和环境工程中的超临界反应及分离过程的开发。 吸附操作对于环境工程具有重要意义，可以通过吸附过程来除去空气中的微量有害物质，以达到保护环境的目的。因此，本文用分子模拟方法考察了狭缝碳孔吸附脱除空气中的少量有机物。模拟时以苯作为有害物质的代表，且为简化起见用氮气代表空气。通过模拟并拟合得到了苯及氮气的化学位与主体压力的关联式。应用GCMC方法考察了狭缝孔宽及主体压力对苯吸附选择性及有效超额吸附量的影响，以确定最佳狭缝孔宽及操作工况。 另外，为了保护环境，回收报废的冰箱、空调器等内的过渡型制冷剂HCFC也是环境工程中的重要课题。因此，本文应用GCMC系综方法模拟研究一氯二更多还原

【Abstract】 With the development of computer science and technology, computer simulation has been becoming a powerful tool in studying both structures and properties of real fluids. It has also been drawn great attention in chemical engineering field. Compared with the traditional method, computer simulation has its special advantages. By performing computer simulation on model fluids, microscopic and macroscopic properties can be revealed, and many physical phenomena can also be discovered and interpreted. Moreover, the macroscopic properties of real fluids can be predicted from the interaction between molecules. In this work, we use the molecular simulation method to calculate the properties of infinite dilute aqueous solutions, to study the hydrophilicity of organic substances in supercritical aqueous solutions and to investigate adsorption processes of fluids in slit pores.At first, five water potential energy models have been investigated by the NPT ensemble Monte Carlo(MC) method, and the transferable intermolecular potential function for four points(TIP4P) model is considered as the best model for simulating the properties of water and aqueous solutions at normal temperatures and pressures. The Henry constants and activity coefficients for methane and benzene in infinite dilute aqueous solutions have been simulated by the NPT ensemble thermodynamic integration with the coupling parameter method. The preferential sampling method has been used for improving the efficiency of the simulation. The TIP4P and the optimized parameters by liquid simulation(OPLS) are proposed for the description of the molecular interactions for water and organic substances, respectively. The Ewald method has been incorporated into the long range correction for the interaction between water molecules. The simulated errors are in fair agreement with the literature data, which indicates that the method used in this work can be applied to the predication of the properties for organic substances in infinite dilute aqueous solutions.The hydrophilicity of benzene in supercritical aqueous solutions has been investigated by the canonical(NVT) ensemble method. The simple point charge(SPC) model and the Lennard-Jones(LJ) model with OPLS parameters have been adopted for the description of interactions between water and benzene molecules, respectively. The effects of the variables, including temperature, concentration and density in 10 cases on the hydrophilicity of benzene have been investigated. The microstructures and the radial distribution functions(RDFs) of the aqueous solutions describe the behavior of benzene molecules changing from hydrophobic to hydrophilic, taking place in the supercritical conditions. As a result, an appropriate condition for benzene molecules dissolving homogeneously in the supercritical water is recommended for the design of reaction更多还原