THERMAL-DECOMPOSITION OF OXALATES .25. THE EFFECT OF SAMPLE PREPARATION AND ENVIRONMENTAL ATMOSPHERE ON THE THERMAL-STABILITY OF COPPER(II) OXALATE

The kinetics and thermal stability of copper oxalate prepared under stoichiometric and non-stoichiometric conditions have been studied by isothermal and rising temperature experiments in nitrogen and in air. In addition, a mechanism-independent method and a computer program were used to interpret the isothermal data to give additional information on the stability of the systems. In nitrogen, the presence of excess copper chloride stabilizes the salt whilst the presence of excess oxalic acid reduces the stability. This trend is also observed for silver oxalate. The interpretations of the stability of the salts based solely on the activation energy were misleading. The use of a computer program shows that a more accurate evaluation requires the consideration of the pre-exponential factor and the reaction mechanism in addition to the activation energy.