Thermal analysis of manganese(II) complexes with L-proline and L-hydroxyproline

The thermal decomposition reactions of manganese(II) complexes with L-proli ne and 4-hydroxy- L-proline were studied. The Mn(II) proline complex loses the water molecule at 40-95 degrees C and then, heated above 250 degrees C it decomposes in several steps to manganese oxide. The most appropriate kin etic equations for dehydration process are the geometrical R2 or R3 ones. T hey give a value of activation energy, E of about 95 kJ mol(-1). The Mn(II) hydroxyproline complex loses the water molecules in two stages (70-110 and 110-230 degrees C) and next it decomposes to manganese oxide in several st eps. The R3 or D3 (three-dimensional diffusion) models are the most appropr iate for the first stage of dehydration (E is about 155 kJ mol(-1)). The se cond step of dehydration is limited by D3 mechanism (E=52 kJ mol(-1)).