2026-04-15T07:31:11Z https://www.eurjchem.com/index.php/eurjchem/oai

oai:ojs.www.eurjchem.com:article/1249 2015-06-30T08:25:37Z eurjchem:ART driver

Non-isothermal decomposition kinetics of theobromine in nitrogen atmosphere Kamel, Laila Tosson Theobromine Šatava-Šesták method Thermal decomposition Thermodynamic parameters Linear isoconversional methods Non‐isothermal kinetic parameters The non-isothermal decomposition process of theobromine under nitrogen atmosphere was studied using the differential thermal analysis (DTA), from room temperature up to 500 °C, at heating rates, 5, 15 and 20 °C/min. The results showed that theobromine decomposes in two steps. The kinetic analysis of the first decomposition step was performed using Kissinger, Friedman, Flynn-Wall-Ozawa, and Kissinger-Akahira-Sunose isoconventional methods. The kinetic model was determined using Šatava-Šesták method. Results showed that the non-isothermal decomposition mechanism of theobromine corresponds to nucleation and growth, following the Avrami-Erofeev equation. The forms of the integral and differential equations for the mechanism function are g(α)=(-ln(1-α))2/3 and f(α)=(3/2)(1-α)(-ln(1-α))1/3, respectively. Thermodynamic parameters of the non-isothermal decomposition process, change of enthalpy (ΔH), change of entropy (ΔS), and change of Gibbs free energy (ΔG) values were calculated. Atlanta Publishing House LLC 2015-06-30 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion application/pdf https://www.eurjchem.com/index.php/eurjchem/article/view/1249 10.5155/eurjchem.6.2.199-203.1249 European Journal of Chemistry; Vol. 6 No. 2 (2015): June 2015; 199-203 2153-2257 2153-2249 eng https://www.eurjchem.com/index.php/eurjchem/article/view/1249/pdf_1249