Non-isothermal decomposition kinetics of theobromine in nitrogen atmosphere

Abstract

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 nonisothermal 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. KEYWORDSTheobromine Šatava-Šesták method Thermal decomposition Thermodynamic parameters Linear isoconversional methods Non-isothermal kinetic parameters Cite this: Eur.

A Novel Low-Temperature Fluorination Roasting Mechanism Investigation of Regenerated Spent Anode Graphite via TG-IR Analysis and Kinetic Modeling

“…The expression from the Šatava–Šesták method was given by the following formula: 37 Different forms of mechanism functions [ g (α)] were linearly fitted with , and the reaction-mechanism function most in line with the experiment was determined according to the fitting results. Meanwhile, according to the optimal mechanism function, the activation energy E s and pre-exponential factor A s can be obtained.…”

Synthesis, characterization and thermal decomposition of ethyl-2’-amino-5’-cyano-6’-(1H-indole-3yl)-2-oxospiro[indoline-3,4’-pyran]-3’-carboxylate under non‐isothermal condition in nitrogen atmosphere

“…The synthesized compounds were evaluated for their antimicrobial activity and all the compounds showed significant activity. Non-isothermal decomposition kinetics of chitosan [8], chitin [9], cephalosporins [10], procaine and benzocaine [11], theobromine [12], spiro-oxindole derivatives [13][14][15], parthenium hysterophorus [16], nitroimidazoles [17] and ferrocene [18] were studied in detail and appropriate kinetic models were proposed.…”

Synthesis, characterization and thermal decomposition of 2’-amino-6’-(1H-indol-3-yl)-1-methyl-2-oxospiro-[indoline-3,4’-pyran]-3’,5’-dicarbonitrile under non-isothermal condition in nitrogen atmosphere

“…Literature data show that no work has been reported on thermal decomposition of spirooxindoles by one-pot multicomponent system at different heating rates (10,15,20 and 30 K/min) under non-isothermal condition in nitrogen atmosphere. In this paper, we report the synthesis and thermal decomposition of 2'-amino-6'-(1H-indol-3-yl)-1-methyl-2-oxospiro[indoline-3, 4'-pyran]-3', 5'-dicarbonitrile ( Figure 1) [17] and its thermal decomposition under nonisothermal dynamic nitrogen atmospheric condition.…”

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