Compensation effect in reactions between trans-4,4'-dinitrostilbene oxide and arylsulfonic acids

作者：Shpan'ko I V^*; Sadovaya I V

来源：Russian Journal of Physical Chemistry, 2016, 90(12): 2332-2338.

DOI：10.1134/S0036024416120268

• trans-4,4 '-dinitrostilbene oxide
• arylsulfonic acids
• isoparametricity phenomenon
• compensation effect
• mechanistic aspects

The effect structure and temperature have on the rate and free activation energy of reactions between trans-4,4'-dinitrostilbene oxide and Y-substituted arylsulfonic acids YC6H4SO3H in a mixture of dioxane with 1,2-dichloroethane (7: 3 vol/vol) at 265, 281, and 298 K is studied. It is found that as a result of the nonadditivity of the joint effect of substituents Y and temperature on the rate of the process of oxirane ring opening, the cross reaction series exhibits isoparametric properties in the aspect of enthalpy-entropy compensation. This allows the experimental determination of an isoparametric point with respect to the constant of substituent Y (sigma(Y) (IP)= 0.52), in which activation entropy Delta S (not equal) = 0 and free activation energy Delta G (not equal) do not depend on temperature (Delta G (not equal) = Delta H (not equal)), and to conduct the transition through this point with inversion of the order of the effect temperature has on the value of Delta G (not equal) as a result of reversing the sign of Delta S (not equal): in the series Y (sigma(Y)) = 4-OCH3 (-0.27), 4-CH3 (-0.17), H (0), 4-Cl (0.23), and 3-NO2 (0.71), the values of Delta S (not equal) (J/(mol K)) are-140,-119,-85,-42, and 44, respectively. The possibility of using isoparametric points as quantitative mechanistic criteria is demonstrated.

• 出版日期2016-12