A physico-geometric approach to the kinetics of solid-state reactions as exemplified by the thermal dehydration and decomposition of inorganic solids

Koga, Nobuyoshi; Tanaka, Haruhiko

doi:10.1016/s0040-6031(02)00051-5

Cited by 132 publications

(120 citation statements)

References 119 publications

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“…The apparent fitting of the kinetic rate data to a nucleation and growth law may result from complex concurrent processes of the surface reaction and established reaction. As is the case of E a , effect of CO 2 higher H 2 O concentration of 8.2 g m −3 , the A value at the higher CO 2 concentration of 0.55 g m −3 is smaller by three orders of magnitude than that at the lower CO 2 concentration of 0.1 g m −3 ; see Table I. As can be seen above, the apparent kinetic behavior and kinetic parameters of the present reaction vary sensitively with very small changes in the reaction atmosphere within the range of the self-generated atmospheric conditions.…”

Section: Kinetic Analysesmentioning

confidence: 81%

Influences of product gases on the kinetics of thermal decomposition of synthetic malachite evaluated by controlled rate evolved gas analysis coupled with thermogravimetry

Koga

Yamada

2005

Int J of Chemical Kinetics

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An instrument of controlled rate evolved gas analysis (CREGA) coupled with TG-DTA was constructed for analyzing the influences of product gases on the kinetics and mechanism of the thermal decomposition of solids that produce more than one gaseous products at the same stage of reaction. The thermal decomposition of synthetic malachite, Cu 2 (OH) 2 CO 3 , was subjected to the measurements of CREGA-TG under controlled concentrations of H 2 O and CO 2 in the reaction atmosphere with taking account of self-generated H 2 O and CO 2 during the course of reaction. By a series of CREGA-TG measurements carried out under various atmospheric conditions, it was reconfirmed that the reaction is accelerated and decelerated by the effects of atmospheric H 2 O and CO 2 , respectively. From the kinetic analysis of the CREGA-TG curves and results of high temperature X-ray diffraction measurements under various reaction atmospheres, it was revealed that the anomalous effects of atmospheric H 2 O on the reactivity and on the reaction rate of the thermal decomposition of synthetic malachite appear at the

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Section: Kinetic Analysesmentioning

confidence: 81%

Influences of product gases on the kinetics of thermal decomposition of synthetic malachite evaluated by controlled rate evolved gas analysis coupled with thermogravimetry

Koga

Yamada

2005

Int J of Chemical Kinetics

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“…5 showed that the activation energy values could easily change by 10 kJ/mol and even more, if some experimental points were excluded, most likely due to particle size dispersion in the measured samples [10]. There can be other factors affecting the reaction rate and thus the acti-vation energy values included the self-heating of reaction interface because of exothermic reaction, changes in water vapour concentration in the reaction interface and the diffusion of water to the reaction interface from the surrounding atmosphere [11,12]. These factors are often considered for dehydration reactions because this type of reactions is well characterized, but the same effects may oppositely influence the hydration reactions.…”

Section: Resultsmentioning

confidence: 99%

Hydration of Xylazine Hydrochloride Polymorphic Forms A, Z and M

Krūkle-Bērziņa¹,

Actiņš²,

Be̅rziņš³

2011

Latvian Journal of Chemistry

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“…The reaction interface was obscured at the later stage by undesirable nuclei, and consequently only the first part of the interfacial movement during the reaction can be evaluated with acceptable accuracy. Figure 4 shows schematically a typical model for the interface advance in a planar geometry [31]. In general, the interface advance involves three processes: (1) breakdown of a reactant constituent by rupture of chemical bonds, (2) structural reorganization of this chemically changed material from the reactant structure (a phase) to the more stable product structure (b phase) and (3) transport of dissociated water molecules through the porous product layer.…”

Section: Microscopy Experiments Of Interface Advancementioning

confidence: 99%

An experimentally validated numerical model of interface advance of the lithium sulfate monohydrate dehydration reaction

Lan

Steenhoven

Rindt

2016

J Therm Anal Calorim

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Interface advance plays an essential role in understanding the kinetics and mechanisms of thermal decomposition reactions such as the dehydration reaction of lithium sulfate monocrystals. However, many fundamental processes including mass transfer during interface advance are still not clear. In this work, the dynamics of interface advance, involving interaction between interfacial reaction and mass diffusion, is investigated numerically together with microscopy observations. A mathematical model is developed for interface advance with a moving boundary and then solved by using a conservative scheme. To examine the significance between the intrinsic chemical reaction and mass diffusion, a Damköhler number is defined as Da ¼ k r L=ðD e c 0 Þ. Numerical results at various Da values are discussed to distinguish the limiting step of the dehydration reaction of lithium sulfate monocrystals. Moreover, experiments are carried out with a hot-stage microscopy system where the propagation of the reaction interface into the crystal bulk is followed in situ. By fitting the experimental results with the numerical results, the effective diffusivity of water through the dehydrated crystal is estimated to be in the order of 10 À8 m 2 s À1 . According to the corresponding Da values, it is found that, within the reaction temperature ranging from 110 to 130°C and a partial water vapor pressure of 13 mbar, the rate of dehydration interface advance in the bulk of large crystals (typically in the order of millimeters) is not constant, but shows a small decrease over time due to the influence of mass diffusion.

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A physico-geometric approach to the kinetics of solid-state reactions as exemplified by the thermal dehydration and decomposition of inorganic solids

Cited by 132 publications

References 119 publications

Influences of product gases on the kinetics of thermal decomposition of synthetic malachite evaluated by controlled rate evolved gas analysis coupled with thermogravimetry

Influences of product gases on the kinetics of thermal decomposition of synthetic malachite evaluated by controlled rate evolved gas analysis coupled with thermogravimetry

Hydration of Xylazine Hydrochloride Polymorphic Forms A, Z and M

An experimentally validated numerical model of interface advance of the lithium sulfate monohydrate dehydration reaction

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