Thermal decomposition of cerium triethanolamine complexes

Abstract

Thermal decomposition of cerium triethanolamine complexes to cerium oxide, CeO2, in inert and oxidative atmospheres has been investigated by thermogravimetry combined with infrared evolved gas analysis; the main volatiles formed during thermal decomposition have been identified. Intermediates and final products have been characterized by infrared spectroscopy, X-Ray diffraction and elemental analysis. Several overlapping steps occurring along decomposition path have been identified and plausible reaction pathways are presented. It will be shown that decomposition starts around 200ºC independently of the atmosphere, but the endset temperature depends on the gas composition: the more inert the atmosphere the higher the endset temperature. Finally, the effect of the temperature and amount of triethanolamine used during compound synthesis is discussed.

Use of thermal analysis to predict the conditions for thermal explosion to occur: application to a Ce triethanolamine complex

“…Ce−TEA was prepared according the procedure described in [38,39]; 10.86 g Cerium(III) nitrate hexahydrate (Ce(NO3)3ꞏ6H2O Alfa Aesar ≥ 99.5%) was dissolved into 200 ml 1−propanol (VWR, ≥ 99.9%) in a round bottom flask under nitrogen at 60ºC using a stirring magnetic hot plate. When a clear solution was obtained, the heating system was shut down.…”

“…From X-ray diffraction, elemental analysis and infrared analysis, Ce−TEA has been identified as the Ce(III) complex: [Ce(NO3)(C6H15NO3)2](NO3)2 [38]. So in the Ce−TEA complex we have two TEA molecules and three nitrate groups per cerium atom.…”

“…Moreover, from Fig 1, it is apparent that the decomposition of Ce−TEA is a complex process. Two main stages have been identified [38]: a fast one that ends around 300ºC (note the elbow at the TG curve) and a slow one that extends up to 800ºC and beyond.…”

“…In this complex, TEA is a reducing agent that acts as fuel while the nitrate group is a strong oxidizer. So Ce−TEA contains both the fuel and the oxidizer and undergoes combustion in the usual conditions used in TA measurements [38][39][40][41].…”