Preparation, thermal decomposition process and kinetics for terbiump-methoxybenzoate ternary complex with 1,10-phenanthroline

Abstract

The complex of [Tb2(p-MOBA)6(PHEN)2] (p-MOBA=C8H7O3,p-methoxybenzoate; PHEN=C12H8N2, 1,10-phenanthroline) was prepared and characterized by elemental analysis and IR spectroscopy. The thermal behavior of Tb2(p-MOBA)6(PHEN)2 in a static air atmosphere was investigated by TG-DTG, DTA, SEM and IR techniques. By the kinetic method of processing thermal analysis data put forward by Malek et al., it is defined that the kinetic model for the first-step thermal decomposition is SB(m,n). The activation energy E for this step reaction is 140.92 kJ mol-1, the enthalpy of activation ΔH≠ is 136.06 kJ mol-1, the Gibbs free energy of activation ΔG≠ is 145.16 kJ mol-1, the entropy of activation ΔS≠ is -15.53 J mol-1, and the pre-exponential factor lnA is 29.26. The lifetime equation at mass loss of 10% was deduced as lnτ =-28.72+1.943·104/T by isothermal thermogravimetric analysis.