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 aZ11.300(2) A ° , bZ12.993(2) A ° , cZ 10.155(1) A ° , bZ98.33(1)o, F(000)Z672, the unit-cell volume VZ1475.2(5) A ° 3, the molecule number in one unit-cell ZZ4, the absorption coefficient mZ1.19 cmK1, the calculated density DcZ1.456 g cmK3. 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)(1Ka)[Kln(1Ka)]1/4, 123.88 kJ molK1 and 1011.49 sK1, respectively. The critical temperature of thermal explosion of the title compound is 161.15 oC and the entropy of activation ðDSsÞ, enthalpy of activation ðDHsÞ, and free energy of activation ðDGsÞ are K34.16 J molK1 KK1, 115.7, and 130.48 kJ molK1, respectively. q 2005 Elsevier B.V. All rights reserved.