The parameters of the Arrhenius equation determined by the linear, weighted linear and non-linear least squares methods and by the simplex method are compared. Since the non-linear least squares method permits the consideration of statistical weights of both the dependent (k) and independent (T) variables and does not involve logarithmic transformation, it is advisable to calculate the parameters of the Arrhenius equation by means of the non-linear least squares method.
The existing methods of approach to solve the integral in the Arrhenius equation (Coats-Redfern, Gorbachev, Zsakó, Balarin etc.), when the standard linearization method of the integral kinetic equation
is applied in order to determine the value of the activation energyE, yield factually identical results. Hence attempts to find more accurate approaches have no practical sense.
Authors:F. J. Lona-Ramírez, R. Herrera-Muñoz, V. Rico-Ramírez, F. Louvier Hernández, G. Luna-Bárcenas, and G. González-Alatorre
work presents the results obtained from a kinetic study of the nitrosation of 1,1,3-nitrosotrimethylurea, including both the validity of the Arrheniusequation and the reaction mechanism.
The solutions were
This paper is a review of some of the controversial kinetic aspects of thermal analysis, starting from the ‘šesták questions’
posed in 1979 and looking at developments in some areas since that time. Aspects considered include: temperature programmes
and variations, models and mechanisms, kinetic parameters, distinguishability and extent of fit of kinetic models, complementary
evidence for kinetic models, the Arrhenius equation and the compensation effect. The value of the ideas of non-isothermal
kinetics in chemical education is emphasized.
Authors:Andrzej Czyrski, Tadeusz Hermann, and Agata Smoląg
calculated from the Arrheniusequation:
where ‘ k ’ is the first order rate constant at temperature ‘ T ’, R is the gas constant, A is the pre-exponential factor and ‘ E a ’ is the Arrhenius activation energy. The error of E a was calculated from the
Authors:D. Bhattacharjya, T. Selvamani, and Indrajit Mukhopadhyay
reaction [ 13 , 14 , 16 ]. For non-isothermal decomposition process, the expression of Eq. 1 can be used in the Arrheniusequation to give an expression:
Equation 2 is the expression for the Friedman isoconversion method which avoids the
Authors:K. Chatterjee, D. Dollimore, and K. Alexander
Hydroxy benzoic acids were subjected to rising temperature thermogravimetric analysis. After optimizing the procedural variables,
the kinetics of decomposition was determined and methyl paraben was taken as the calibration compound to characterize the
evaporation patterns for the ortho and meta derivatives. The Eact values for ortho, meta and para derivatives were 64.8, 78.2, and 119.1 kJ mol–1, respectively. The Antoine and Langmuir equations were utilized to determine the coefficient of evaporation k, which was 1245250.8, units being in the SI system. The vapor pressure plots were generated for the ortho and meta derivatives; ΔHvap for these two compounds were obtained as 66.7 and 80.4 kJ mol–1, respectively.
-conversional methods, Ozawa–Flynn–Wall (OFW) method [ 15 – 17 ], Kissinger–Akahira–Sunose (KAS) method [ 18 , 19 ] and Popescu (P) method [ 20 ] have been widely used to estimate the activation energies E , pre-exponential factor A in Arrheniusequation and the