Preparation, crystal structure and thermal decomposition kinetics of 1-(2,4-dinitrophenyl)azo-1-nitrocyclohexane

A new three-nitro-group compound of 1-(2,4-dinitrophenyl)azo-1-nitrocyclohexane was prepared by the reaction of cyclohexanone-2,4-dinitrophenylhydrazine with nitric oxide at ambient temperature. The single crystal structure has been determined by a four-circle X-ray diffractometer. The compound is monoclinic with space group P2(1)/c and unit-cell parameters a = 11.300(2) angstrom, b = 12.993(2) angstrom, c = 10.155(1) angstrom, beta = 98.33(1)degrees, F(000) = 672, the unit-cell volume V=1475.2(5) angstrom(3), the molecule number in one unit-cell Z = 4, the absorption coefficient mu = 1.19 cm(-1), the calculated density D-c = 1.456 g cm(-3). The exothermic decomposition reaction kinetics of the compound has been studied by DSC. The kinetic model function in differential form, apparent activation energy and pre-exponential constant of this reaction are (3/4)(1 - alpha)[-ln(1 - alpha)](1/4), 123.88 kJ mol(-1) and 1011.49 s(-1), respectively. The critical temperature of thermal explosion of the title compound is 161.15 degrees C and the entropy of activation (Delta S-not equal), enthalpy of activation (Delta H-not equal), and free energy of activation (Delta G(not equal)) are - 34.16 J mol(-1) K-1, 115.7, and 130.48 kJ mol respectively. (c) 2005 Elsevier B.V. All rights reserved.