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  • Author or Editor: C. Donghua x
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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  

Reliable kinetic information for thermal analysis kinetic triplets can be determined by the comparative method: (1) An iterative procedure or the KAS method had been established to obtain the reliable value of activation energy E a of a reaction. (2) A combined method including Coats-Redfern integral equation and Achar differential equation was put forward to confirm the most probable mechanism of the reaction and calculate the pre-exponential factor A. By applying the comparative method above, the thermal analysis kinetic triplets of the dehydration of CaC2O4H2O were determined, which apparent activation energy: 813 kJ mol-1, pre-exponential factor: 4.51106-1.78108 s-1, the most probable mechanism function: f(α)=1 or g(α)=α, which the kinetic equation of dehydration is dα/dt=Ae-E a /RT.

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