{\rtf1\ansi\ansicpg1250\deff0\deflang1038\deflangfe1038\deftab708{\fonttbl{\f0\froman\fprq2\fcharset238{\*\fname Times New Roman;}Times New Roman CE;}} \viewkind4\uc1\pard\f0\fs20 Processing of non-isothermal TG data \par }

Vlase, Gabriela; Doca, N.; Bolcu, Constantin

doi:10.1007/s10973-005-0613-x

Cited by 42 publications

(3 citation statements)

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“…To perform the kinetic analysis of the TG experimental data, we used three isoconversional methods, a differential one (Friedman) and two integral ones (Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose methods), respectively a fourth method elaborated by Sempere et al [29,30] and modified and developed by Vlase et al [31,32,33], the non-parametric kinetics method (NPK), in order to obtain realistic kinetic parameters.…”

Section: Resultsmentioning

confidence: 99%

“…The non-parametric kinetics method (NPK) elaborated by Sempere et al [29,30] and modified and developed by Vlase et al [31,32,33] is based on the assumption that the reaction rate can be expressed as a product of two independent functions, f (α): a function of the degree of conversion and k ( T ): a temperature dependence, so the validity of Equation (1) is the only assumption made in the development of the NPK method. The reaction rates for several measurements at different β can be written as an n × m matrix whose rows correspond to constant value of conversion degree and whose columns account for the different but constant values of temperature.…”

Section: Resultsmentioning

confidence: 99%

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Synthesis and Degradation of Schiff Bases Containing Heterocyclic Pharmacophore

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Alexa

Bercean

et al. 2015

IJMS

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Synthesis and Degradation of Schiff Bases Containing Heterocyclic Pharmacophore

Ledeți

Alexa

Bercean

et al. 2015

IJMS

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“…To perform the kinetic analysis of the experimental data such as TG and DSC, there were used two isoconversional methods, a differential one and an integral one, respectively a third method elaborated by Sempere et al [14,15] and modified and developed by Vlase et al [16-18], the non-parametric kinetics method.…”

Section: Resultsmentioning

confidence: 99%

Comparative kinetic analysis on thermal degradation of some cephalosporins using TG and DSC data

Fuliaş

Vlase

et al. 2013

Chemistry Central Journal

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BackgroundThe thermal decomposition of cephalexine, cefadroxil and cefoperazone under non-isothermal conditions using the TG, respectively DSC methods, was studied. In case of TG, a hyphenated technique, including EGA, was used.ResultsThe kinetic analysis was performed using the TG and DSC data in air for the first step of cephalosporin’s decomposition at four heating rates. The both TG and DSC data were processed according to an appropriate strategy to the following kinetic methods: Kissinger-Akahira-Sunose, Friedman, and NPK, in order to obtain realistic kinetic parameters, even if the decomposition process is a complex one.The EGA data offer some valuable indications about a possible decomposition mechanism. The obtained data indicate a rather good agreement between the activation energy’s values obtained by different methods, whereas the EGA data and the chemical structures give a possible explanation of the observed differences on the thermal stability. A complete kinetic analysis needs a data processing strategy using two or more methods, but the kinetic methods must also be applied to the different types of experimental data (TG and DSC).ConclusionThe simultaneous use of DSC and TG data for the kinetic analysis coupled with evolved gas analysis (EGA) provided us a more complete picture of the degradation of the three cephalosporins. It was possible to estimate kinetic parameters by using three different kinetic methods and this allowed us to compare the Ea values obtained from different experimental data, TG and DSC. The thermodegradation being a complex process, the both differential and integral methods based on the single step hypothesis are inadequate for obtaining believable kinetic parameters. Only the modified NPK method allowed an objective separation of the temperature, respective conversion influence on the reaction rate and in the same time to ascertain the existence of two simultaneous steps.

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