Kinetics and mechanism of the thermal decomposition reaction of 3,6-diphenyl-1,2,4,5-tetroxane in solution.

In the temperature range of 130-166 degrees C, the thermolysis of 3,6-diphe nyl-1,2,4,5-tetroxane in toluene and methanol solutions in the initial conc entration ranges of (1.1 - 15.6).10(-3) mol kg(-1) and (0.56 - 1.9) 10(-3) mol kg(-1), respectively, follows first order kinetic laws. The activation parameters for the unimolecular reaction in toluene (Delta H*(148 degrees C ) = 31.2 +/- 0 6 kcal mol(-1); Delta S*(148 degrees C) = -6.9 +/- 1.5 cal m ol(-1) K-1; Delta G*(148 degrees C) = 34.1 +/- 0.8 kcal mol(-1)), and in me thanol (Delta H*(148 degrees C) = 25.3 +/- 0.8 kcal mol(-1); Delta S*(148 d egrees C) = -15.3 +/- 1.8 cal mol(-1) K-1, Delta G*(148 degrees C) = 31.7 /- 0.8 kcal mol(-1)) indicate a significant solvent effect which support ho molytic stepwise mechanisms of reaction instead of conr certed processes. H owever, in both cases the main organic product is benzaldehyde which is par tially oxidized in the solutions to benzoic acid.