Enthalpy of Formation of 3-Methylfurazan-4-yl Radical

摘要

This study is aimed at determining the energy of dissociation of the C-NO2 bond in 3-methyl-4-nitro-furazan (I) and the enthalpy of formation of the 3-methylfurazan-4-yl radical (II). The enthalpy of formation of I in the standard state and in the gas phase has been determined for the first time. A procedure has been suggested for calculation of the C-NO2 bond dissociation energy in cyclic aromatic compounds from experimental differences between the enthalpies of atomization of nitro and corresponding alkyl derivatives of the compound to be studied and reference cyclic aromatic compounds. In the procedure, the unknown energies of rearrangement of molecular fragments into radicals are mutually excluded, and the resulting values reflect the ratio of bond dissociation energies in compared cyclic aromatic structures. This procedure enables the determination of bond dissociation energies and enthalpies of formation of radicals without using kinetic data on thermal decomposition of the compound to be studied. On the basis of this method, the dissociation energy of the C-NO2 bond in I and the enthalpy of formation of II have been determined for the first time. This procedure is promising for cyclic aromatic compounds of different composition and structure for which necessary kinetic data are not available for some reasons. In particular, 4-substituted 3-alkylfurazans and furoxans undergo monomolecular cyclodecomposition at the N-O and C-C bonds to give intermediate nitriles and nitrile oxides [1].