Studies on energetic compounds: Part 35: kinetics of thermal decomposition of nitrate complexes of some transition metals with propylenediamine

Abstract

Five bis(propylenediamine)metal nitrate (BPMN) complexes such as [M(pn) 2](NO 3) 2 (where M = Cr, Mn, Ni, Cu, Zn, and pn = propylenediamine) have been prepared and characterized by gravimetric methods, infrared and elemental analysis. Their thermal decomposition has been studied using simultaneous thermogravimetry -differential thermal analysis in atmospheres of nitrogen and air to examine the effect of the atmosphere on the thermolysis of these complexes. Several measurable changes were recorded in the mode of decomposition of all these complexes when the atmosphere was changed from nitrogen (inert) to air (reactive). However, as indicated by thermoanalytical techniques, the thermal stability of these complexes decreases in the order: Cr > Mn > Zn > Ni > Cu. Isothermal thermogravimetry, over the temperature range of deamination (ie, the loss of an amine ligand) has been performed for all the complexes. An analysis of the kinetics of deamination of these complexes was made using a model fitting procedure, as well as an isoconversional method independent of any model. The merits and demerits of both kinetic approaches have been discussed. The ignition delay (t id) was measured to investigate the trends of rapid thermolysis. All these complexes were found to be insensitive to an impact test in which a hammer (2 kg weight) was used.