Mixed solvent influence on the conformer equilibrium

Typically, in specific solvents, the process of monomer formation [9.57] is characterized by considerably lower dimerization constants, as compared with those in universal media. In fact, acetic acid dimerization constant in water-dioxane binary solvent, the components of which are solvation-active in respect to the acid, vary in the 0.05-1.2 range. Replacing the solvent is often the only method to vary the molecular association state of dissolved compound. To achieve dimer concentration in 0.1 M solution of phenol in n-hexane equal to dimer concentration in nitrobenzene solution (50% at 25 C), it would be necessary to heat the solution to 480 C, but it is impossible under ordinary experimental conditions. 9.4.3 MIXED SOLVENT INFLUENCE ON THE CONFORMER EQUILIBRIUM Equilibrium took place in solutions 

It is evident that the aceuracy of the experimental definition of equilibrium eonstants of the investigated proeess is insuffieient. Thus, the summarization of experimental data on solvent effeet on [9.60, 9.61] equilibrium eneounters several diffieulties. 

As a rule, the differenees in eonformer energies are not very high and ehange from one tenth to 10-12 kJ/mol. This is one order value with dipole-dipole interaetion and speeifie solvation energies, even in low-aetive solvents. Moreover, the dipole moments of eon- 

If equations of processes are identical to that of scheme [9.45] in the form and maintenance, it is possible to apply the equations from Section 9.4.1 to calculate the equilibrium 

Abrahem worked out details of the solvent effect theory on changing equilibrium. This theory also accounts for the quadruple interactions with media dipoles. It demonstrates that the accuracy of this theory equations is not better than that obtained from an ordinary 

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