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) Å, b=12.993(2) Å, c=10.155(1) Å, β=98.33(1)o, F(000)=672, the unit-cell volume V=1475.2(5) Å3, the molecule number in one unit-cell Z=4, the absorption coefficient μ=1.19 cm−1, the calculated density Dc=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−α)[−ln(1−α)]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 oC and the entropy of activation (ΔS≠), enthalpy of activation (ΔH≠), and free energy of activation (ΔG≠) are −34.16 J mol−1 K−1, 115.7, and 130.48 kJ mol−1, respectively.