Thermodynamic Studies of the Effects of Solvents on Molecular Complex Formation Equilibria;Orientation of Water Around Nonpolar in Solutes Aqueous Solutions.

摘要

The effect of solvents on electron-donor-acceptor complex formation reactions has been studied thermodynamically. The nonpolar analog model (NPA) is examined theoretically and methods are developed for using it to predict thermodynamic properties of the transfer of donor,acceptor,complex molecules from the gas phase into dilute solutions in nonpolar solvents. Thermodynamic results calculated by using the NPA model,in conjunction with solubility parameter theory and the Prigogine refined average-potential cell model theory,are compared with experimental results for polar components involved in several molecular complex formation equilibria. For individual solutes,including complexes,calculated and experimental free energies of transfer into hexadecane,diphenylmethane,heptane,cyclohexane, carbontetrachloride,and benzene generally agree to within 0.1to 0.7Kcal/mole. Application of the nonpolar analog model has been made for the prediction of solvent effects on molecular complex formation constants.