Analysis and prediction of the Arrhenius parameters of low-temperature thermolysis of nitramines by means of the 15N NMR spectroscopy

The paper presents N-15 NMR chemical shifts delta of 24 nitramines out of which 1-nitro-1-azaethylene, 1,3-dinitro-1,3-diazacyclobutane and 1,3,5,7,9-pentanitro-1,3,5,7,9-pentaazacyclodecane have not been synthesized yet. The relationships between the Arrhenius parameters E-a and log A of the low-temperature thermolysis under conditions of Russian manometric method and delta values of nitrogen atoms in nitro groups are specified for substances studied. The delta values correspond to nitro groups in nitramino groupings which are the first to undergo thermolysis. On the basis of the relationships specified the E-a and log A values are predicted for 13 compounds from the nitramines studied, the parameters of homolytic course of thermolysis are differentiated from those of bimolecular or another heterolytic thermal decomposition, some aspects of the thermolysis of nitramines, particularly with geometrical constraints and/or with strongly-withdrawing groups in their molecules, are interpreted and evaluation of effect of solid-liquid phase transition on the kinetics of initial stage of HMX thermolysis are made. (C) 1999 Elsevier Science B.V. All rights reserved.