The study of decomposition reactions through the exchange of thermal energy

Constantinou, Constantinos

doi:10.1002/kin.550261203

Cited by 6 publications

(3 citation statements)

References 30 publications

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“…Unimolecular CN Bond Scission. Unimolecular CN bond scission has been proposed in connection with thermal decomposition work at relatively low pressures. , However, at higher pressures, this mechanism was not supported. − Likewise, in the present work, CN scission is not a favored mechanism. The early broadening of the CH 3 peak, given the lack of early changes in the CN peak, cannot be explained by this mechanism.…”

Section: Discussion Of Resultscontrasting

confidence: 66%

Shock-Induced Chemical Changes in Neat Nitromethane: Use of Time-Resolved Raman Spectroscopy

Winey

Gupta

1997

J. Phys. Chem. B

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Time-resolved Raman spectroscopy was used to examine chemical changes in neat liquid nitromethane subjected to stepwise loading to peak pressures of 14−17 GPa. After a peak pressure at 14 GPa was reached, no changes in the CN (917 cm-1), NO2 (1400 cm-1), and CH3 (2968 cm-1) symmetric stretching modes were observed. After a peak pressure at 16 GPa was reached, time-dependent changes were observed during the induction period reported in previous absorption experiments. At this peak pressure, the extent of reaction was small, and the observed changes in the CH3 and CN modes indicated prereaction changes in the sample bulk. After a peak pressure at 17 GPa was reached (980 K peak temperature), all three peaks disappeared, indicating that the extent of reaction was substantial under these conditions. The broadening of the CH3 peak and the softening of the CN mode observed in this work suggest strong intermolecular interactions. These interactions lead to a reaction precursor involving proposed head-to-tail intermolecular associations with decomposition proposed to follow through a bimolecular reaction, put forward by Bardo, which forms nitrosomethane and nitromethanol. Confirmation of these ideas will require different spectroscopic methods, since Raman measurements are primarily useful for probing initial changes in the sample.

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Section: Discussion Of Resultscontrasting

confidence: 66%

Shock-Induced Chemical Changes in Neat Nitromethane: Use of Time-Resolved Raman Spectroscopy

Winey

Gupta

1997

J. Phys. Chem. B

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“…In the nucleation and growth model, n is a function of the nucleation barrier and the geometry of the growth. Values of n ≈ 3 suggest three-dimensional growth (spheres or hemispheres), values of n ≈ 2 indicate two-dimensional growth (disks and cylinders), and n ≈ 1 is typically due to linear growth. − ,, …”

Section: Kinetic Analysismentioning

confidence: 99%

Decomposition Kinetics of the AlH₃ Polymorphs

2005

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Aluminum hydride polymorphs (alpha-AlH3, beta-AlH3, and gamma-AlH3) were prepared by organometallic synthesis. Hydrogen capacities approaching 10 wt % at desorption temperatures less than 100 degrees C have been demonstrated with freshly prepared AlH3. The temperature-dependent rate constants were determined by measuring the isothermal hydrogen evolution between 60 degrees C and 140 degrees C. Fractional decomposition curves showed good fits using both the second and third-order Avrami-Erofeyev equations, indicating that the decomposition kinetics are controlled by nucleation and growth of the aluminum phase in two and three dimensions. The large activation energies measured for the AlH3 polymorphs suggest that the decomposition occurs via an activated complex mechanism with complexes consisting of approximately nine AlH3 molecules (1-2 unit cells for alpha-AlH3).

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“…The isothermal approach may be preferable when the objective is reaction order determination (Constantinou, 1994). Although reactions of primary interest in food processing often Author Welt, involve complex mechanisms and multiple pathways, most follow apparent first-order kinetics with Arrhenius temperature dependence (Labuza, 1979).…”

Section: Introductionmentioning

confidence: 99%

Iterative Method for Kinetic Parameter Estimation from Dynamic Thermal Treatments

Welt

Teixeira

Balaban

et al. 1997

Journal of Food Science

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The purpose of this work was to utilize the Equivalent Point Method (EPM) for kinetic parameter estimation from dynamic thermal treatments. An assumption which was fundamental to the EPM, however, when found invalid led to the development of an alternative approach, the method of Paired Equivalent Isothermal Exposures (PEIE). The method provided conceptual simplicity and ease-of-use as well as improved accuracy and reproducibility. The fundamental assumption of the EPM was tested on a mathematical basis, and demonstrated with example calculations. Development of the PEIE method was explained and described with procedural steps. Sample calculations described implementation details of PEIE. The method successfully estimated Arrhenius kinetic parameters from realistic, arbitrary, dynamic thermal treatments.

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The study of decomposition reactions through the exchange of thermal energy

Cited by 6 publications

References 30 publications

Shock-Induced Chemical Changes in Neat Nitromethane: Use of Time-Resolved Raman Spectroscopy

Shock-Induced Chemical Changes in Neat Nitromethane: Use of Time-Resolved Raman Spectroscopy

Decomposition Kinetics of the AlH₃ Polymorphs

Iterative Method for Kinetic Parameter Estimation from Dynamic Thermal Treatments

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The study of decomposition reactions through the exchange of thermal energy

Cited by 6 publications

References 30 publications

Shock-Induced Chemical Changes in Neat Nitromethane: Use of Time-Resolved Raman Spectroscopy

Shock-Induced Chemical Changes in Neat Nitromethane: Use of Time-Resolved Raman Spectroscopy

Decomposition Kinetics of the AlH3 Polymorphs

Iterative Method for Kinetic Parameter Estimation from Dynamic Thermal Treatments

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Product

Resources

About

Decomposition Kinetics of the AlH₃ Polymorphs