Mechanisms of Noncatalytic Organic Chemical Reactions in Super- and Subcritical Water

引入了稀溶液中分子构型的能量表示，以表示溶剂在溶质周围的分布，在一维坐标上表示溶质-溶剂相互作用能。在这种表示中，溶质-溶剂相互作用势集与分布函数集之间的对应关系是一对一的。在这种对应关系的基础上，通过在溶质-溶剂相互作用的排斥区采用类percuss - yevickk近似，在吸引区采用类超网状链近似，构造了溶质在溶液中的化学势的近似泛函。然后，化学势与溶剂密度和溶质-溶剂相互作用的关系精确地为二阶。结果表明，在广泛的热力学条件下，非极性、极性和离子溶质在水中的化学势可以通过单一功能准确而有效地评估。此外，纳米级分子（如蛋白质）的构象在溶质-溶剂相互作用下变化很大。因此，需要建立具有构象柔性的溶质分子的溶剂化自由能的方法来处理具有功能重要性的溶液体系。能量表示方法被扩展到处理柔性溶质分子的溶剂化自由能。在这项工作中，我们研究了分子内运动的拉伸和/或扭转自由度的水中溶质系统，并证明了该方法在广泛的热力学条件下的性能，包括环境和超临界。疏水溶质和亲水溶质在水中的聚集行为也在同一框架内进行了研究。

The energy representation of the molecular configuration in a dilute solution is introduced to express the solvent distribution around the solute over a one-dimensional coordinate specifying the solute-solvent interaction energy. In this representation, the correspondence is shown to be one-to-one between the set of solute-solvent interaction potentials and the set of distribution functions On the basis of the one-to-one correspondence, an approximate functional for the chemical potential of a solute in solution is constructed by adopting the Percus-Yevick-like approximation in the repulsive region of the solute-solvent interaction and the hypernetted-chain-like approximation in the attractive region. The chemical potential is then given exactly to second order with respect to the solvent density and to the solute-solvent interaction. It is demonstrated that the chemical potentials of nonpolar, polar, and ionic solutes in water are evaluated accurately and efficiently from the single functional over a wide range of thermodynamic conditions. Furthermore, the conformation of a nanoscale molecule such as protein varies strongly in response to solute-solvent interactions. An approach to the solvation free energy of a solute molecule with conformational flexibility thus needs to be established toward treating a solution system of functional importance. The method of energy representaion is extended to treat the solvation free energy of a flexible solute molecule, In this work, we examined solute systems in water with stretching and/or torsioal degrees of freedom for intramolecular motion, and demonstrated the performance of the method over a wide range of thermodynamic conditions including both ambient and supercritical. The aggregation behaviors of hydrophobic and hydrophilic solutes in water are also treated within the same framework.