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Abstract  

A new method of the multiple rate iso-temperature was used to define the most probable mechanism g(α) of a reaction; the iterative iso-conversional procedure has been employed to estimate apparent activation energy E a, the pre-exponential factor A was obtained on the basis of E a and g(α). In this new method, the thermal analysis kinetics triplet of dehydration of calcium oxalate monohydrate is determined, which apparent activation energy E a is 82.83 kJ mol-1, pre-exponential factor A is 1.142105-1.235105 s-1, the most probable mechanism belongs to phase boundary reaction Rn with integral form g(α)=1-(1-α)n and differential form f(α)=n(1-α)1-(1/n), where accommodation factor n=2.40-1.40.

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Abstract  

The title compound 3,3-dinitroazetidinium (DNAZ) 3,5-dinitrosalicylate (3,5-DNSA) was prepared and the crystal structure has been determined by a four-circle X-ray diffractometer. The thermal behavior of the title compound was studied under a non-isothermal condition by DSC and TG/DTG techniques. The kinetic parameters were obtained from analysis of the TG curves by Kissinger method, Ozawa method, the differential method and the integral method. The kinetic model function in differential form and the value of E a and A of the decomposition reaction of the title compound are f(α)=4α3/4, 130.83 kJ mol−1 and 1013.80s−1, respectively. The critical temperature of thermal explosion of the title compound is 147.55 °C. The values of ΔS , ΔH and ΔG of this reaction are −1.35 J mol−1 K−1, 122.42 and 122.97 kJ mol−1, respectively. The specific heat capacity of the title compound was determined with a continuous C p mode of mircocalorimeter. Using the relationship between C p and T and the thermal decomposition parameters, the time of the thermal decomposition from initiation to thermal explosion (adiabatic time-to-explosion) was obtained.

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Abstract

3,3-Dinitroazetidinium (DNAZ) salt of perchloric acid (DNAZ·HClO4) was prepared, it was characterized by the elemental analysis, IR, NMR, and a X-ray diffractometer. The thermal behavior and decomposition reaction kinetics of DNAZ·HClO4 were investigated under a non-isothermal condition by DSC and TG/DTG techniques. The results show that the thermal decomposition process of DNAZ·HClO4 has two mass loss stages. The kinetic model function in differential form, the value of apparent activation energy (E a) and pre-exponential factor (A) of the exothermic decomposition reaction of DNAZ·HClO4 are f(α) = (1 − α)−1/2, 156.47 kJ mol−1, and 1015.12 s−1, respectively. The critical temperature of thermal explosion is 188.5 °C. The values of ΔS , ΔH , and ΔG of this reaction are 42.26 J mol−1 K−1, 154.44 kJ mol−1, and 135.42 kJ mol−1, respectively. The specific heat capacity of DNAZ·HClO4 was determined with a continuous C p mode of microcalorimeter. Using the relationship between C p and T and the thermal decomposition parameters, the time of the thermal decomposition from initiation to thermal explosion (adiabatic time-to-explosion) was evaluated as 14.2 s.

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In defense of thermodynamics

Comment on “Concepts against mathematics: self-inconsistency in thermodynamic evaluations”

Journal of Thermal Analysis and Calorimetry
Author: Robert H. Swendsen

]. From the differential form of the fundamental relation in the energy representation, we see that Because the energy of the classical ideal gas is where k B is Boltzmann's constant, we have Using the ideal gas law, PV = Nk B T , the energy

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Differential form is given by: 9 The average of activation energy ( E ) calculated through Friedman equation and Kissinger equation was 156.12 kJ mol −1 , and the average of lg A -value was 5.61 s −1 . Therefore, the thermal decomposition of magnesite

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isoconversional variant were the two conducting ideas of the kinetic analysis strategy. This will be applied to the first process, i.e., to the dehydration. At a constant conversion the differential form of the reaction rate can be written: 1 where α

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) Friedman’s differential isoconversional method [ 7 ] The generally accepted differential form of the reaction rate under non-isothermal conditions and constant conversion is: 1 where β is the heating rate, T is the reaction temperature, and

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conducting ideas of the kinetic analysis strategy. This will be applied to the first process. At a constant conversion, the differential form of the reaction rate can be written: where α is the conversion degree, β is the heating rate, T is

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) Differential form of kinetic mechanism function G ( α ) Integral form of the kinetic mechanism function n

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derive the underlying reaction mechanism. These methods state that the reaction rate at a constant extent of conversion is only a function of the temperature [ 30 ]. Equation 1 is the differential form of Friedman and Eqs. 2 and 3 are the basic

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