The Rate of the Diels‐Alder Cycloaddition Reactions of Benz(a)Anthracene With Tetracyanoethylene and 4‐Phenyl‐1,2,4‐triazoline‐3,5‐dione in Solution and Solid State

ABSTRACT The data on solvent and temperature influence on the rates of Diels‐Alder reactions of benz(a)anthracene with tetracyanoethylene and 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione were experimentally obtained. The activation enthalpies and entropies for these reactions in several organic solvents were determined. For the reaction of benz(a)anthracene with tetracyanoethylene, the equilibrium constants in some solvents were measured as functions of temperature, and the reaction enthalpies and entropies have been calculated. The kinetics of benz(a)anthracene‐tetracyanoethylene and benz(a)anthracene‐4‐phenyl‐1,2,4‐triazoline‐3,5‐dione reactions upon crystal grinding in a vibration ball mill was studied. Based on the obtained and literature data, we concluded that, for Diels‐Alder reactions, the rate and equilibrium in the solution correlate with the rate and equilibrium in the solid state.