Journal of thermal analysis

, Volume 41, Issue 2–3, pp 387–404 | Cite as

The non-isothermal decomposition of cobalt acetate tetrahydrate

A kinetic and thermodynamic study
  • M. A. Mohamed
  • S. A. Halawy
  • M. M. Ebrahim
Solid State Decompositions


The non-isothermal decomposition of cobalt acetate tetrahydrate was studied up to 500°C by means of TG, DTG, DTA and DSC techniques in different atmospheres of N2, H2 and in air. The complete course of the decomposition is described on the basis of six thermal events. Two intermediate compounds (i.e. acetyl cobalt acetate and cobalt acetate hydroxide) were found to participate in the decomposition reaction.

IR spectroscopy, mass spectrometry and X-ray diffraction analysis were used to identify the solid products of calcination at different temperatures and in different atmospheres. CoO was identified as the final solid product in N2, and Co3O4 was produced in air. A hydrogen atmosphere, on the other hand, produces cobalt metal. Scanning electron microscopy was used to investigate the solid decomposition products at different stages of the reaction. Identification of the volatile gaseous products (in nitrogen and in oxygen) was performed using gas chromatography. The main products were: acetone, acetic acid, CO2 and acetaldehyde. The proportions of these products varied with the decomposition temperature and the prevailing atmosphere.

Kinetic parameters (e.g.E and lnA) together with thermodynamic functions (e.g. °H, C p and °S) were calculated for the different decomposition steps.


cobalt acetate tetrahydrate IR kinetics MS non-isothermal decomposition thermodynamic study TG-DTG-DTA-DSC X-ray 


In verschiedenen Atmosphären aus N2, H2 und in Luft wurde mittels TG, DTG, DTA und DSC bis zu 500°C die nichtisotherme Zersetzung von Kobaltacetat-Tetrahydrat untersucht. Der gesamte Umsetzungsprozeß wird auf der Grundlage von sechs thermischen Ereignissen beschrieben. Man fand, daß zwei Zwischenprodukte (Acetylkobaltacetat und Kobalt-acetathydroxid) an den Zersetzungsreaktionen beteiligt sind.

Die Bestimmung der Feststoffprodukte der kalzinierung bei verschiedenen Temperaturen und in verschiedenen Atmosphären erfolgte mittels IR-Spektroskopie, Massenspektrometrie und Röntgendiffraktion. In Stickstoff entsteht als festes Endprodukt CoO, in Luft hingegen Co3O4. In Wasserstoffatmosphäre kommt es jedoch zur Bildung von metallischem Kobalt. Mittels Scanning-Elektronenmikroskopie wurden die festen Zersetzungsprodukte zu verschiedenen Reaktionsstadien untersucht. Die Bestimmung flüchtiger gasförmiger Produkte (in Stickstoff und in Sauerstoff) erfolgte mittels Gaschromatographie. Die Hauptprodukte waren: Aceton, Essigsärue, CO2 und Acetaldehyd, deren relative Menge von der Zersetzungstemperatur und der vorherrschenden Temperatur abhängt.


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Copyright information

© Wiley Heyden Ltd, Chichester and Akadémiai Kiadó 1994

Authors and Affiliations

  • M. A. Mohamed
    • 1
  • S. A. Halawy
    • 1
  • M. M. Ebrahim
    • 1
  1. 1.Department of Chemistry, Faculty of ScienceQenaEgypt

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