Kinetics and thermodynamic parameters of the thermal decomposition of bis(imipraminium)tetrachlorocuprate, bis(imipraminium)tetrachloromercurate and imipraminium reineckate

Non-isothermal and isothermal decompositions of the above ion-pairs have been studied and the results were statistically analyzed. The thermal decomposition reaction of each ion-pair is shown to be a two-steps reaction and each step is a first-order reaction. The kinetic parameters: activation energy, Ea, and the pre-exponential term, A, were calculated for each step of the reaction. The theory of activated complex has been applied to each step of the reaction and the thermodynamic functions ΔH≠, ΔG≠ and ΔS≠ are calculated. A stiff and rigid activated complex (transition state) led to a lower degrees of freedom of rotation and vibration and hence to a negative value of ΔS≠ is obtained which means the formation of a stiff and rigid activated complex (transition state) with fewer degrees of freedom of rotation and of vibration. The thermal stability of the studied complexes varies in the order: imipraminium reineckate ≫ bis(imipraminium)tetrachloromercurate(II) > bis(imipraminium)tetrachlorocuprate(II).