Kinetics of the Diels–Alder Reaction of Dibenz[a,h]anthracene with 4-Phenyl-1,2,4-triazoline-3,5-dione in Solution and in the Solid Phase

The kinetics of the Diels–Alder reaction of dibenz[a,h]anthracene with 4-phenyl-1,2,4-triazoline-3,5-dione in solution and in the solid phase without solvent by manual grinding of the reagents with a pestle in a mortar were studied. The equilibrium constants of the reaction and the rate constants of the forward and reverse reactions in 1,2-dichloroethane in the temperature range 308–348 K were determined, the activation parameters of the forward and reverse reactions were calculated, and the enthalpy and entropy of the reaction were determined. It was found that the kinetic curve of the Diels–Alder reaction of dibenz[a,h]anthracene with 4-phenyl-1,2,4-triazoline-3,5-dione in the solid phase is S-shaped with an initial induction period. The limiting yield of the adduct after 120 min of grinding the reagents with a pestle in a mortar was 68%.