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apparent activation energy ( E a ) for dissociation of Mn(CO) 5 from solid Mn 2 (CO) 10 . Unlike traditional mass spectrometry (which involves ionization by high-energy electrons), EGA-IAMS offers a considerable advantage in that it preserves the structure

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Co-firing of biomass with coals

Part 1. Thermogravimetric kinetic analysis of combustion of fir (abies bornmulleriana) wood

Journal of Thermal Analysis and Calorimetry
Authors: Ahu Gümrah Dumanli, Sinem Taş, and Yuda Yürüm

be illustrated by (2) where A is the pre-exponential Arrhenius factor, E the activation energy, and R the gas constant. For dynamic data obtained at a constant heating rate this term is inserted in Eq. 2 so the above rate

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predictions, especially due to the combination of factors such as heat transfer, mass transfer phenomena, chemical reactions, and thermal stability [ 3 , 6 , 7 ]. Knowledge of kinetic parameters as activation energy and pre-exponential factor would help

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Thermal decomposition of acrylamide from polyacrylamide

Time-resolved pyrolysis with ion-attachment mass spectrometry

Journal of Thermal Analysis and Calorimetry
Authors: Yuki Kitahara, Ko Okuyama, Keita Ozawa, Takuya Suga, Seiji Takahashi, and Toshihiro Fujii

to the ion source, and hence primary degradation products may be observed by this technique, compared with conventional pyrolysis–GC/MS (Py–GC/MS). Apparent activation energies for decomposition of acrylamide EGA

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Preparation of the Ca–diclofenac complex in solid state

Study of the thermal behavior of the dehydration, transition phase and decomposition

Journal of Thermal Analysis and Calorimetry
Authors: Marcelo Kobelnik, Douglas Lopes Cassimiro, Clóvis Augusto Ribeiro, Diógenes dos Santos Dias, and Marisa Spirandeli Crespi

at temperatures corresponding to fixed values of conversion degree (α) and the activation energy ( E a /kJ mol −1 ) data were obtained applying the isoconversional method proposed by Capela and Ribeiro [ 9 ]. Experimental

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Catalyst Rate constant k (h −1 ) Activation energy (E a ) (kJ/mol) Pre-exponential factor (A) (mol −1 h −1 ) Enthalpy (ΔH # ) (kJ mol −1

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. Calculation of the activation energy by isoconversional method Thermal transformation of crystal hydrates is a solid-state process of the type [ 22 – 28 ]: A(solid) → B (solid) + C (gas). The kinetics of such reactions is described by various

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Summary  

Mechanism of the processes in condensed phase are very often unknown or too complicated to be characterised by a simple kinetic model. They tend to occur in multiple steps that have different rates. To describe their kinetics, the single-step kinetics approximation is often applied which resides in substituting a generally complex set of kinetic equations by the sole single-step kinetics equation. The main contribution of the single-step kinetics approximation is that it enables a mathematical description of the kinetics of solid-state reactions without a deeper insight into their mechanism. The single-step kinetics approximation is based on the assumption that the temperature and conversion functions are separable. In the paper, some consequences originating from ignoring the function separability are discussed.

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Abstract  

The TG studies are presented for isomers of benzimidazolyl-substituted polyamides (BIPA). The TG data are compared with those polyamides (PA) of identical backbones without substitution, in view of the mechanism of thermal degradation. The TG mass loss curves divided to three temperature ranges reflect the decomposition reactions in the respective temperature ranges: (1) cleavage of single bonds of nitrogen to aromatic ring, (2) random scission of single bonds, (3) condensation of the remained rings. Liberation of benzimidazole rings occurs in the temperature range (2). The final product, char, contains benzimidazole rings. Terephthaloyl-rich BIPA's retard liberation of benzimidazole from the decomposed polymer.

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The thermochemical behaviour of solid-state complexes of lanthanum with mono-(2-ethylhexyl) phosphoric acid (H2B) (La(HB)3·1.5H2O and La2B3·3H2O) was studied. The thermal decomposition of these complexes proceeds without melting to yield La(PO3)3 and a mixture of La(PO3)3 and LaPO4, respectively. La(HB)31.5H2O decomposes via dehydration (323–383 K), condensation of the OH-groups with formation of a diphosphate structure (383–458 K) and a stepwise degradation of the hydrocarbon chains (443–565 K). The dehydration of La2B3·3H2O (333–433 K) is followed by decomposition of the hydrocarbon group. From a combination of the present results with previous data [1], it was concluded that the temperatures and mechanisms of the decomposition of the hydrocarbon part of the lanthanide complexes of (2-ethylhexyl) phosphoric acids depend on the nature of the lanthanide, the atmosphere, and the structure of the complexes.

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