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The enthalpies of formation of nitromethane derivatives were obtained on the basis of experimental and literature data. The procedure for the calculation of the bond dissociation energies in nitromethanes from the atomization enthalpies and energies of nonvalent interac tions of nitro groups was proposed. The calculated values were compared with the data on the thermal decomposition kinetics. The atomization enthalpies and energies of nonvalent interac tions of nitro groups were also used for the calculation of the bond dissociation energies in radicals.The bond dissociation energies and formation enthal pies of radicals are most important energy characteristics of molecules and intermediate reaction products (inter mediates). These values determine stability of compounds and affect the mechanism and kinetics of conversion of substances, including the intensity of chain processes. 1 The bond dissociation energies and enthalpies of forma tion of radicals and substances in the gas phase are related by the equationwhere D(R 1 -R 2 ) is the dissociation energy of compound R 1 R 2 to radicals R 1 and R 2 ; ΔH°f(R 1 ), ΔH°f(R 2 ), and ΔH°f(R 1 R 2 ) g are the formation enthalpies of radicals R 1 , R 2 , and compound R 1 R 2 in the gas phase under standard conditions. It follows from Eq. (1) that the dissociation energy of bond is equal to the energy that should be tran ferred to the molecule (radical) for its dissociation to rad icals R 1 and R 2 . The dissociation energies of bonds are usually determined by using the kinetic data on the activa tion energies (Е а ) of monomolecular radical reactions of thermal decomposition. It is assumed 1 that the enthalpy of backward process (formation of a molecule from radi cals) is zero. For such compounds as polynitroalkanes, nitrates, and secondary nitroamines, thermal decomposi tion proceeds as the monomolecular radical reaction with the dissociation of the C-NO 2 , O-NO 2 , or N-NO 2 radicals. 2,3 If the enthalpy of the backward reaction of radical association is considered equal to zero, then the dissociation energy of the R-NO 2 bond is equal to the activation energy of thermal decompositionIt was concluded 4 on the basis of the theory of absolute reaction rates that the difference between D and E a in cludes RT and depends on the differences between the heat capacities of the products and reactants in the disso ciation reaction and on the differences of the heat capaci ties of the transition state and initial radicals in recombi nation. The integrals taken of the heat capacity differenc es have different signs, and various molecules at certain temperatures exactly obey Eq. (2).The differences between D and E a can be estimated from the statistical mechanics equations if the parameters of geometric structures, inter nal rotation barriers, and vibration frequencies of poly atomic particles are known. These calculations are rather difficult for the classes of compounds studied in this work and, hence, we will use Eq. (2).Equations (1) and (2) are used for the determination of...

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It is proposed to supplement a phase diagram by a structural diagram, which represents the mass portions of phases, conglomerates or their elements upon the system concentration at fixed temperature. Methods of structural diagrams and concentration maps construction are considered. Concentration map is a projection of structural diagram. It marks a concentration triangle by the lines of constant mass portions of a phase or its elements. INTRODUCTIONPhase diagram of binary and ternary system is used to visualize the component interaction results and to store in compact form the data. It becomes more informative if to supplement its concentration simplex by a structural diagram. The last can serve also as an instrument to design heterogeneous material with a help of concentration maps marked by the lines of constant mass portions of microstructure elements or its conglomerates [1].

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