scholarly journals COMF: Comprehensive Model-Fitting Method for Simulating Isothermal and Single-Step Solid-State Reactions

Crystals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 139
Author(s):  
Yannis Vasilopoulos ◽  
Eliška Skořepová ◽  
Miroslav Šoóš
Keyword(s):  
Solid State ◽  
Model Fitting ◽  
Single Step ◽  
Solid State Reactions ◽  
Comprehensive Model ◽  
Ranking Criterion ◽  
Fitting Method ◽  
Reaction Speed ◽  
Selection Of

It is well known that the implementation of the conventional model-fitting (CMF) method leads to several indistinguishable ‘best’ candidate models (BCMs) for a single-step isothermal solid-state reaction (ISSR), meaning that subjective selection becomes unavoidable. Here, we developed a more robust comprehensive model-fitting method (COMF) which, while maintaining the mathematical simplicity of CMF, utilizes a ranking criterion that enables automatic and unambiguous determination of the BCM. For each model evaluated, COMF, like CMF, fits the integral reaction rate, but, unlike CMF, it also fits the experimental conversion fraction and reaction speed. From this, three different determination coefficients are calculated and combined to rank the considered models. To validate COMF, we used two sets of experimental kinetic data from the literature regarding the isothermal desolvation of pharmaceutical solvates: (i) tetrahydrofuran solvates of sulfameter, and (ii) methanol solvates of ciclesonide. Our results suggest that from an algorithmic perspective, COMF could become the model-fitting method of choice for ISSRs making the selection of BCM easier and more reliable.

Untersuchungen zum ternären System Bi/Te/O, III. Bestimmung thermodynamischer Daten der ternären Verbindungen/Investigations on the Ternary System Bi/Te/O,III. Determination of Thermodynamic Data of Ternary Compounds

1999 ◽  
Vol 54 (2) ◽  
pp. 252-260 ◽  
Author(s):  
P. Schmidt ◽  
C. Hennig ◽  
H. Oppermann
Keyword(s):  
Solid State ◽  
Ternary System ◽  
Thermodynamic Data ◽  
Phase Relations ◽  
Solid State Reactions ◽  
Enthalpies Of Formation ◽  
Ternary Compounds ◽  
Heats Of Solution

The phase relations in the ternary system Bi/Te/O have been determined in previous studies by solid state reactions. Thermodynamical data have now been obtained for the pertinent equilibria. The heats of solution of Bi2O3, Bi12TeO20, Bi10Te2O19, Bi16Te5O34, Bi2TeO5, Bi2Te2O7, Bi2Te4O11 and TeCl4 were determined in 4N HCl. From these the enthalpies of formation of bismuth tellurites at 298 K have been derived:⊿H°b (Bi12TeO20, f, 298) = -901,6 ± 8 kcal/mol,⊿H°b (Bi10Te2O19, f, 298) = -856,1 ± 9 kcal/mol,⊿H°b (Bi16Te5O34, f, 298) = -1519,5 ± 17 kcal/mol,⊿H°b (Bi2TeO5, f, 298)= -222,8 ± 3 kcal/mol,⊿H°b (Bi2Te2O7, f, 298)= -299,4 ± 4 kcal/mol,⊿H°b (Bi2Te4O11, f, 298)= -448,2 ± 7 kcal/mol.

Theory of nucleation in solid state reactions

1968 ◽  
Vol 46 (2) ◽  
pp. 111-116 ◽  
Author(s):  
A. R. Allnatt ◽  
P. W. M. Jacobs
Keyword(s):  
Solid State ◽  
Approximate Model ◽  
Single Step ◽  
Solid State Reactions ◽  
Avrami Equation ◽  
Nucleation Process ◽  
Special Cases ◽  
New Equation ◽  
Kinetics Of ◽  
Short Times

The theory of nucleation in solid state reactions is formulated in a general way and a solution to the problem of multi-step nucleation obtained. Two special cases of the general formulation are considered: the second of these corresponds to Bagdassarian's approximate model and some corrections to his treatment are pointed out. A new equation describing the kinetics of a solid state reaction, which involves multi-step nucleation followed by a constant and isotropic rate of growth, is derived. This equation is termed the generalized Avrami equation since it removes the restriction, in Avrami's treatment, of a single-step nucleation process. Erofeev's analysis of the problem is shown to be valid only in the limit of short times: the generalized Avrami equation reduces to Erofeev's equation in this limit.

scholarly journals Advanced Research of the Triassic Clay from the Baltic Region

2012 ◽  
Vol 51 (4) ◽  
pp. 376-382
Author(s):  
J. Karasa ◽  
J. Kostjukovs ◽  
A. Palaša ◽  
A. Actiņš
Keyword(s):  
Solid State ◽  
Quantitative Determination ◽  
Organic Molecules ◽  
Clay Fraction ◽  
Solid State Reactions ◽  
Baltic Region ◽  
X Ray ◽  
Smectite Clays ◽  
The Baltic

A procedure of smectite containing clay enrichment has been optimized, and the process of sedimentation has been studied. The new enrichment based method for quantitative determination of clay fraction in smectite containing sediment was developed. A new method for obtaining organoclays from enriched smectite clays has been investigated. The method is based on solid-state reaction between smectite and organic compounds, where organic molecules can be intercalated in dried clay mineral (montmorillonite) by solid-state reactions, without or with use of solvents. The enriched clay and the obtained organoclay samples were characterized with X-ray powder diffraction (PXRD).

Application of non-linear heating regime for the determination of activation energy and kinetic parameters of solid-state reactions

1998 ◽  
Vol 323 (1-2) ◽  
pp. 101-107 ◽  
Author(s):  
K.V Tomashevitch ◽  
S.V Kalinin ◽  
A.A Vertegel ◽  
N.N Oleinikov ◽  
V.A Ketsko ◽  
...  
Keyword(s):  
Activation Energy ◽  
Solid State ◽  
Kinetic Parameters ◽  
Solid State Reactions ◽  
Heating Regime ◽  
Linear Heating ◽  
Non Linear
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