Synthesis and Thermo analytical studies of 5-(4-fluoro-3-phenoxyphenyl)-4, 5-dihydro-3-(3, 4-dimethoxyphenyl) -1-(2, 4-dinitrophenyl)-1H-pyrazole in nitrogen atmosphere - Non-isothermal condition

Abstract

In the present study, a pyrazoline compound 5-(4-fluoro-3-phenoxyphenyl)-4,5-dihydro-3-(3,4-dimethoxyphenyl)-1-(2,4-dinitrophenyl)-1H-pyrazole (DMPDN) has been syntheszed by refluxing respective chalcone with 2,4-dinitrophenylhydrazine in acidic medium and characterized by physical constant and spectroscopic techniques (FT-IR), NMR (¹H and ¹³C) and Mass spectra. The thermal decomposition of DMPDN was studied by thermogravimetry under nitrogen atmosphere at different heating rates of 10, 15 and 20 K min^–1. The decomposition process of DMPDN is occurred in single step as evidenced from thermogram. The kinetic parameters were calculated using model free methods (Friedman, Kissinger-Akahira-Sucrose (KAS) and Flynn-wall-Ozawa (FWO)) and model-fitting method [Coats Redfern (CR)]. The calculated invariant kinetic parameters of DMPDN are consistent with the average values obtained by Friedmann and KAS isoconversional method of decomposition is followed different kinetic models. The kinetic thermal decomposition of DMPDN was described by a A3 model.