【作者】 刘波；

【导师】 黄世萍；

【作者基本信息】 北京化工大学 ， 化学工程与技术， 2011， 硕士

【摘要】 不管是自然万物生化过程还是各种化学生产过程,大多数的化学反应都是在溶液中进行的。溶剂化效应作为一种普遍存在的现象,它对溶液中的分子微观结构和热力学性质都有重要的影响,研究其对化学反应速率、反应平衡和反应机理的影响,对工业产品的经济高效生产都有着重要的影响。参考作用点模型理论计算作为目前研究分子流体结构最为可靠的方法,它还能计算出溶剂化效应的各种热力学性质。此外,采用GAUSSIAN03程序分别优化和计算了溶液中的分子结构和热力学性质,并将其结果与参考作用点模型理论计算的结果进行了比较。本文主要内容有：1.应用RISM理论计算了二甲基亚砜摩尔分数为0.002下的不同温度下的溶液的微观结构性质和热力学性质。计算结果表明,DMSO加入到水中能够增强溶液的分子网络结构。温度升高,配位数减小,溶液中分子排布趋向无序。平均力势的波动增大表明分子间的诱导力表现为斥力。计算得到的各种热力学性质显示：温度升高,溶液的熵和溶剂化自由能增加,相互作用能和过剩化学位也增加,即高温下溶液越来越偏离理想溶液；空位形成能降低表明溶液分子结构在高温下更容易重组。2.应用RISM理论计算了TMAO摩尔分数为0.002下的298 K下的溶液的微观结构性质和热力学性质。比较和分析了溶液中TMAO分子与水分子间各原子对的径向分布函数变化情况。列举了并分析了溶液中溶剂化效应所产生的热力学性质的影响,结果表明TMAO使得溶液结构更加稳定,分子排布更加有序,是一个放热熵减过程。3.使用GAUSSIAN03程序对TMAO水溶液的溶剂化效应进行了量子计算,得到了TMAO分子全原子优化后的结构,列出了相应原子间的键长和键角,计算了溶剂化效应的热力学性质,并与RISM计算结果进行了比较,相关热力学量均比较接近。更多还原

【Abstract】 Whether biochemical processes of the natural world or various chemical production processes, most of the chemical reactions are carried out in solution. Solvent effect is a widespread phenomenon, which has a major impact on the structural and thermodynamic properties. Studying chemical reaction rate, reaction equilibrium and reaction mechanism has an important economic impact on the efficient production of industrial products. As the most reliable method to study the molecular fluid structure, referenced interaction site model can also calculate the various thermodynamic properties of solvent effect. In addition, the molecular structure and solvation thermodynamic properties are carried out by GAUSSIAN 03 program. The results are compared with those of RISM. The main contents are summarized as follows:1. The structural and thermodynamic properties of aqueous dimethyl sulfoxide at a mole fraction of 0.002 were investigated using Referenced Interaction Site Model theory at 298 K. The results reveal that the water network structure is enhanced by the presence of DMSO. The increased fluctuation in the potential of mean force suggests that the water-induced force is repulsive. In addition, the increased entropy of solvation and free energy of solvation imply that the randomness of the solution increases with an increase in temperature. The increased interaction energy and excess chemical potential reveal that the solution deviates from an ideal solution. Furthermore, the increased cavity reorganization energy shows that the system structure reorganizes easily at high temperature.2. The structural and thermodynamic properties of aqueous TMAO at a mole fraction of 0.002 were investigated using Referenced Interaction Site Model theory at 298 K. We analyse the radial distribution functions of the TMAO molecules and water molecules pairs in solution and the solvent effect on the thermodynamic properties. The results reveal that the molecular structure in solution becomes more stable and orderly. The solvation process is radiative and entropy consumption.3. The solvent effect of aqueous TMAO is studied by GAUSSIAN03 program. We carry out the optimized structure by the all atoms model and list the bond length and bond angel. In addition, we compute the thermodynamic properties by the program, which are consistent with those of RISM.更多还原