Evolved Gas and Kinetic Studies Analysis of Nickel Amine Complexes in the Solid State

摘要

Thermal behaviour of nickel amine complexes containing SO42-, NO3-, Cl- andBr- as counter ions and ammonia and ethylenediamine as ligands have beeninvestigated using simultaneous TG/DTA coupled with mass spectroscopy (TG/DTAMS)Evolved gas analyses detected various transient intermediates during thermaldecomposition. The nickel ammonium sulphate complex produces NH, N, S, O andN2 species. The nickel ammonium nitrate complex generated fragments like N, N2,NO, O2, N2O, NH2 and NH. The halide complexes produce NH2, NH, N2 and H2species during decomposition. The ligand ethylenediamine is fragmented as N2/C2H4,NH3 and H2. The halide complexes produced nano sized metallic nickel as theresidue. Sulphate and nitrate containing amine complexes produced NiO as the finalresidue in the nano range.Kinetic parameters for different stages of thermal decomposition of thecomplexes were evaluated using four non-mechanistic equations viz., Coats–Redfern (CR),Madusudanan-Krishnan-Ninan (MKN), Horowitz-Metzger (HM) and MacCallum-Tanner(MT).The ammine containing complexes undergo stepwise deamination to formcomplexes with lower ammine content. Among the complexes studied the nitratecontaining complexes undergo simultaneous oxidation and reduction. Thedecomposition pattern of hexaamminenickel(II) sulphate complex is identical both inair and helium. For the tris(ethylenediamne)nickel(II) sulphate decomposition, changein reaction atmosphere produced different residues. Hexaamminenickel(II) chlorideand bromide complexes produce metallic nickel with different morphologies as thedecomposition products.