Kinetics of thermolysis of some transition metal nitrate complexes with 1,6-diaminohexane ligand

Abstract

Metal nitrate complexes of general formula [M(dah) 2](NO 3) 2 (where M = Zn, Cu and Ni; dah = 1,6-diaminohexane) have been prepared and characterized by elemental analysis, infrared spectroscopy (IR) and gravimetric method. The thermal decomposition has been studied using thermogravimetry (TG). Simultaneous thermogravimetry–differential thermogravimetry–differential thermal analysis (TG–DTG–DTA) and differential scanning calorimetry (DSC) were done in N 2 atmosphere. Isothermal TG of initial decomposition of all these complexes, have been carried out to evaluate the kinetics of early thermolysis. Both, model fitting and isoconversional method have been used for the evaluation of the kinetics of thermal decomposition. Model fitting method have given the single value of activation energy ( E) whereas, isoconversional method yields a series of E-value, which vary with extent of conversion. Ignition of the complexes was measured to see the response towards rapid heating with varying amounts. The thermal stability of the complexes was found to be in the order as [Zn(dah) 2](NO 3) 2 > [Cu(dah) 2](NO 3) 2 ≈ [Ni(dah) 2](NO 3) 2.