Synthesis, spectral characterization and thermal analysis of rubrocurcumin and its analogues

Rubrocurcumin and its analogues were synthesized and characterized by UV, IR, NMR and FT-MS spectral data. Thermal analysis of compounds has been carried out using TG-DTG techniques using non-isothermal heating conditions. Flynn–Wall–Ozawa and Kissinger–Akahira–Sunose isoconversional methods were used to determine the apparent activation energies ( E a ) for the thermal decomposition rubrocurcumin and its analogues. The E a values obtained using these methods were used as reference to determine the most suitable kinetic model using Coats–Redfern method. A possible mechanism is suggested to explain the thermal decomposition process. From the TG-DTG data, kinetic parameters have been calculated and were used to evaluate the thermal stability of compounds and the substituent effect on its thermal stability.