Procedure for generation of catalyst-free PE-TG profiles and its consequence on calculated activation energies

Berčič, Gorazd; Djinović, Petar; Pintar, Albin

doi:10.1007/s10973-016-5872-1

Cited by 11 publications

(13 citation statements)

References 43 publications

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“…Interestingly this study is also a vindication of Friedman's method for application in energetic material decomposition. It also confirms the claimed efficiency of isoconversional methods in describing kinetics of reactions with complex reaction mechanisms [39, 40, 44, 45].…”

Section: Introductionsupporting

confidence: 78%

“…Advanced integral method when applied to HAN thermal TG data with the suggested [47] smaller limits intervals of integration (i. e. Δ α =0.01–0.02) for optimum results, the obtained activation energy values are either negative (Figure S2b, inset; supplementary information file) or extremely high and hence, unrealistic as values are way different from reported values in the literature from other studies [17, 18, 25, 26, 35, 48, 49]. According to a recommendation by Berčič [44, 45], integration limit interval should be decided on the basis of TG data and should be subjective. Hence, Δ α interval value was varied from 0.02 to 0.7.…”

Section: Resultsmentioning

confidence: 99%

“…As mentioned earlier, for differential method to function optimally, TG data needs to be smoothed out. In the present study a well‐known Savitzky‐Golay smoothing procedure was adopted [39, 40, 44, 45]. The optimization of f value in Savitzky‐Golay smoothing, for HAN thermal decomposition TG data at 20 °C/min is shown in Figure 1 & 3.…”

Section: Resultsmentioning

confidence: 99%

“…Isoconversional method facilitates determination of activation energy ( Ea , kJ/mol) from thermal analysis data using a model‐free calculation [38–40]. Current study focusses on application of two different isoconversional methods, a differential method (Friedman's method) [39, 40, 44, 45] and an advanced integral method (Popescu‐Ortega's method) [40] on the thermal and catalytic decomposition of HAN which is extremely complex due to the autocatalytic and multistep reaction mechanism involved. To obtain Arrhenius constant A CE , compensation effect was employed, and the details of the calculation and validation of compensation effect or isokinetic effect are provided in supplementary information file.…”

Section: Methodsmentioning

confidence: 99%

“…The main drawback of the differential Friedman's analysis is the need for smoothing of integral data like TG signals which otherwise may lead to noisy derivatives of TG signals after the process [39]. The kinetics calculations using differential method was performed on raw TG data which rendered a very scattered activation energy profile (see Figure S2a, supplementary information file) with unreasonable values justifying the importance of smoothing [39, 40, 44, 45] to achieve realistic results. The smoothing method chosen was Savitzky‐Golay method since it reduces noise by fitting segments/window of data to a polynomial function.…”

Section: Methodsmentioning

confidence: 99%

See 4 more Smart Citations

Kinetics and Mechanism of Thermal and Catalytic Decomposition of Hydroxylammonium Nitrate (HAN) Monopropellant

Agnihotri

Oommen

2021

Propellants Explo Pyrotec

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Hydroxylammonium nitrate (HAN) monopropellant with its low sensitivity, volatility and toxicity, not only promises a safer substitute to hydrazine but also offers a higher specific impulse and a positive oxygen balance. This study primarily explores the decomposition mechanism and underlying kinetics for a newly developed cerium oxide‐based catalyst. The chemical kinetics involved in the thermal and catalytic decomposition was examined through an isoconversional method using thermogravimetric analysis (TG) data. The activation energy (Ea) was evaluated using differential isoconversional method (Friedman's method) and advanced integral isoconversional method (Popescu‐Ortega's method). To find frequency factor, compensation effect method (ACE) and intercept method (A0) were used. Advanced integral method could not provide realistic kinetic parameters while differential method predicted values similar to reported values for thermal decomposition. The values obtained for thermal decomposition were found matching with reported values obtained by other techniques which validated the methodology adopted. The reaction mechanism for both thermal and catalytic decomposition were proposed based on evolved gas analysis. The mechanism proposed was able to describe the variable kinetic parameters extracted from isoconversional method. Overall Ea of thermal decomposition of HAN was ∼95 kJ/mol. The decomposition over ceria‐based catalyst was distributed over three stages namely inception, peak and decay with Ea of ∼33 kJ/mol, ∼170 kJ/mol and ∼130 kJ/mol, respectively. Under identical conditions, iridium‐based catalyst show two decomposition stages with Ea of ∼65 kJ/mol and ∼120 kJ/mol while final stage being evaporation of HNO3. The ceria catalyst favoured N2 formation, increased decomposition of HNO3 and enhanced decomposition enthalpy.

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Section: Introductionsupporting

confidence: 78%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 3 more Smart Citations

Kinetics and Mechanism of Thermal and Catalytic Decomposition of Hydroxylammonium Nitrate (HAN) Monopropellant

Agnihotri

Oommen

2021

Propellants Explo Pyrotec

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Evaluation of reaction rate of thermogravimetric analysis data using periodic sinc function interpolation

Aghili,

Shabani

2024

Int J of Chemical Kinetics

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The periodic sinc function interpolation offers a compelling solution to address the issue of noise in the analysis of thermogravimetric analysis (TGA) data, thereby enhancing the outcomes of differential techniques such as the Friedman isoconversional method. In this study, we introduce a novel approach that leverages the periodic sinc function interpolation to directly obtain smooth reaction rates from TGA data, eliminating the reliance on numerical differentiation methods. The efficacy of this method has been confirmed through its application to noisy experimental data derived from the thermal decomposition of various polymers, showcasing its robustness. Readers are provided with the corresponding code for Gnu Octave, serving as a free alternative to MATLAB. Additionally, the activation energies calculated from the experimental data using both the Friedman method and periodic sinc function interpolation closely align with those determined by the integral Vyazovkin method, emphasizing the validity and reliability of this new approach.

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Evaluation of smooth reaction rate of noisy experimental data using Legendre series expansion

Aghili,

Shabani

2024

J Math Chem

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The accurate calculation of reaction rates from experimental data is crucial for understanding and characterizing chemical processes. However, the presence of noise in experimental data can introduce errors in rate calculations. In this study, we introduced a novel approach that utilizes the Legendre series expansion method to directly derive smooth reaction rates from noisy experimental data, eliminating the need for numerical differentiation methods. This approach proves to be highly effective in handling noisy thermogravimetric analysis (TGA) data obtained from the thermal decomposition of specific polymers. We demonstrated the robustness and reliability of this method and provided Gnu Octave codes as a free alternative to MATLAB, making the implementation more accessible. Furthermore, the smooth reaction rates obtained were used to evaluate the activation energy using the Friedman isoconversional method. The results showed excellent agreement with those obtained using the Vyazovkin integral method. Additionally, the proposed method can be applied to obtain smooth derivative thermogravimetric (DTG) curves using noisy TGA data set.

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Procedure for generation of catalyst-free PE-TG profiles and its consequence on calculated activation energies

Cited by 11 publications

References 43 publications

Kinetics and Mechanism of Thermal and Catalytic Decomposition of Hydroxylammonium Nitrate (HAN) Monopropellant

Kinetics and Mechanism of Thermal and Catalytic Decomposition of Hydroxylammonium Nitrate (HAN) Monopropellant

Evaluation of reaction rate of thermogravimetric analysis data using periodic sinc function interpolation

Evaluation of smooth reaction rate of noisy experimental data using Legendre series expansion

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