The thermal and detailed kinetic analysis of dipicolinate complexes

Abstract

The [Cu(pydc)(eim)3]·H2O (1), [Cu(pydc)(4hp)(H2O)] (2) and [Ni(pydc)(3hp)(H2O)2][Cu(pydc)(3hp)(H2O)2]·3H2O (3) complexes (H2pydc = 2,6-pyridinedicarboxylic acid or dipicolinic acid, eim = 2-ethylimidazole, 4hp = 4-hydroxypyridine, 3hp = 3-hydroxypyridine) were studied by thermo-gravimetric analysis at an ambient temperature up to 1000 K under nitrogen atmosphere. The complexes are stable about 350 K, and the decomposition reactions were carried out in seven, three and four stages for the complexes 1, 2 and 3, respectively. Following detailed thermo-gravimetrical analysis of the complexes, the decomposition mechanism was suggested for all complexes. The kinetic analysis of all decomposition stages of each compound was performed except for the final stages. The values of the activation energy, Ea, were obtained using model-free Kissinger–Akahira–Sunose and Flyn–Wall–Ozawa methods for all decomposition stages. © 2016, Akadémiai Kiadó, Budapest, Hungary.