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

Abstract

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) Å 3, the molecule number in one unit-cell Z=4, the absorption coefficient μ=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−α)[−ln(1−α)] 1/4, 123.88 kJ mol −1 and 10 11.49 s −1, respectively. The critical temperature of thermal explosion of the title compound is 161.15 oC and the entropy of activation ( Δ S ≠ ) , enthalpy of activation ( Δ H ≠ ) , and free energy of activation ( Δ G ≠ ) are −34.16 J mol −1 K −1, 115.7, and 130.48 kJ mol −1, respectively.