Non-isothermal decomposition of cadmium itaconate monohydrate in different atmospheres

Non-isothermal decomposition of cadmium itaconate monohydrate (C5H4O4Cd (.) H2O) was studied between ambient temperature and 600 degreesC in different dynamic atmospheres of N-2, H-2 and air. A number of thermal analysis techniques, e.g. thermogravimetric analysis (TGA), derivative thermogravimetry (DTG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC), were used to monitor the dehydration and decomposition processes. Three main thermal events were observed. X-ray diffraction analysis (XRD) and infrared (IR) spectroscopy were used to identify the solid reaction intermediates and products at different decomposition stages and under different gas atmospheres. Cadmium oxide (CdO) was the only solid product obtained from the decomposition in air. In N2, the product solid was dominated by cadmium oxide together with traces of cadmium metal and cadmium hydroxide (Cd(OH)(2)). In H-2 atmosphere, however, cadmium metal was produced as the major product that sublimes above 450 degreesC. Gas chromatography (GC) was used to identify the main volatile products which were CO2 and CO. Kinetic and thermodynamic parameters of the dehydration and decomposition processes were calculated for all processes in different gas atmospheres studied. (C) 2002 Published by Elsevier Science B.V.