Kissinger s method

Originally proposed as a method for calculating kinetic parameters for reactions of the type solid solid + gas from DTA experiments, Kissinger s method [7] also assumes that the reaction rate is described by equation 5.8. The most important additional assumption of this method is that the maximum in the DTA curve occurs at the same temperature as the maximum reaction rate. The reaction is further assumed to proceed at a rate which varies with temperature and therefore the position of the DTA peak is a function of heating rate. From the variation in the peak temperature with heating rate E can be calculated for any value of n. The maximum reaction rate occurs when d/(h(x/(h) = 0. From equation 5.8 it follows that... 

Based on Kissinger s method, the computation of the apparent activation energy is found to be 224 kJ/mol and 202 kJ/mol in nitrogen and air environments, respectively, for polyimide. The activation energies determined from the Ozawa and Kissinger methods are comparable. 

The kinetic parameters can be estimated according to Kissinger s method [27] from the dependence of the exothermal peak temperature of DSC curves on heating rate. Knowing the reaction order, the maximum point of the DSC curve, dHjdt vs T, is used to obtain the ratio E/n from the expression [28] ... 

The Kissinger s method [138] has been used to estimate the activation energy of the thermal degradation, involving the maximum temperature (Tam) of the first derivative weight loss curves in TGA measurements at a constant heating rate, and the resulting equation can be expressed as follows ... 

Apart from this approach which implies the evidence of Tmax, there is another which includes the value of peak width in the analysis. Also, many authors rely on the application of other, even more simplified methods that enable the calculation of kinetic parameters. Particularly popular among surface scientists are the Redhead s and Kissinger s methods. 

For the SDT data, we considered only mass loss for kinetic analysis. Instability of the DTA baseline meant that results were inconclusive as to whether the mass loss corresponds to an endothermic or exothermic reaction or some combination thereof Kissinger s method yielded A = 2.19x1013 s-1 and E = 173.5 kj/ mol, with a standard error of 8.7 kj/mol on the activation energy. The Freidman parameters are shown in Figure 3 and are approximately equal to the Kissinger value. The AKTS code with its baseline optimization feature has less noise at low conversion, but the two programs agree very well overall. 

As described in section B, DTA and DSC data may also be acquired and processed by the systems previously discussed (5,6,54,56). Vernon (56) used the Borchardt and Daniels (26) and Kissinger (27) methods to calculate and Z of explosive materials from nonisothermai DSC data. Roger s method (57) was used for these calculations from isothermal DSC data. 

In this study, the temperature of maximal peak intensity of desintercalation was detected with the variation of heating rate of 5, 7, 10, 15 and 20 deg./min. in an inert atmosphere. The estimated activation energies by Kissinger s and Ozawa s methods are shown in Fig. 1, 2 and 3. 

Potentiometry is a technique traditionally employed for the quantification of ions in a liquid solution. It is a static electroanalytical method, that is, there is no current flow inside the measurement cell (f = 0). The measurement cell is constituted by two electrodes which are immersed in the solution containing the analytes. A voltmeter measures the potential difference between the two electrodes, which is a fimction of the concentration (actually, the activity) of the analytes, as described by the well-known Nerst s equation (Kissinger and Heineman, 1996). 

A = quantity of heat (meal) corresponding to the area under DSC curve ((mcal/s) s). By the Kissinger method (Boudart), one can determine the activation energy (E) via DSC curves obtained under three different heating rates (P) at least. Once the rates (P) are known, as well as temperatures corresponding to the maximum on each peak (Tc), it is possible to establish the following linear relationship ... 

From 1973 to 2005. the annual number of journal articles on voliamme-try and amperometry grew at three times and two and onc-half limes, respectively, the rate of production of articles in all of chemistry Somc general references on voltammetry include. A. J. Bard and L. R. Faulkner. Electrochemical Methods, 2nd ed., New York Wiley, 2(Xjl S. P. Kounaves. in Handbook of Instrumental Techniques for Analytical Chemistry, Frank A, Settle, ed.. Upper Saddle River. NJ Prentice-Hall. 1997, pp. 711-28 Laboratory Techniques in Electroanalytical Chemistry, 2nd ed P. T. Kissinger and W, R. Heineman, eds,. New York Dekker. 1996 Artalyiical i oltammeiry, Nf. R. Smyih and F. G. os. eds.. New York Elsevier, 1 2. 

A suspension of a-hydroxylaminopropionitrile in benzene shaken and treated with small portions of p-benzoquinone, then refluxed 3-5 hrs. on a steam bath a-oximinopropionilrile. Y 41-64%.—This is a general method for the prepn. of the previously difficultly accessible ot-oximinonitriles. F. e. s. L. W. Kissinger and H. E. Ungnade, J. Org. Chem. 25, 1471 (1960). 

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