Formation of hydrotrioxides during ozonation of hydrocarbons on silica gel. Decomposition of hydrotrioxides

Hydrotrioxides (HT), ROOOH, from isopentane, 1,4-dimethylcyclohexane, 1,3-dimethylcyclohexane, decalin and triphenylmethane were synthesized for the first time by low-temperature ozonation of the corresponding hydrocarbons on a silica surface. Thermal decomposition of hydrotrioxides is accompanied by the formation of radicals and by infrared and visible chemiluminescence (CL). In solution the HTs form self-associates and react reversibly with the solvent (acetone) producing Bayer-Villiger type intermediates (unsymmetrical dialkyl trioxides). These reactions cause a complex character of the decomposition kinetics of HTs, as evidenced by monitoring the dependence of CL intensity on time. Activation parameters of thermal decomposition of HTs show a compensation effect (logA vs E_A) which describes well the available experimental and theoretical data for the homolysis of organic trioxides.