scholarly journals Thermodynamic Assessment of the AF–CrF3 (A = Li, Na, K) and CrF2–CrF3 Systems

Thermo ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 205-219
Author(s):  
Thomas Dumaire ◽  
Rudy J. M. Konings ◽  
Anna Louise Smith
Keyword(s):  
Molten Salt ◽  
Binary Systems ◽  
Thermodynamic Assessment ◽  
Excess Properties ◽  
Alkali Cations ◽  
Reactor Technology ◽  
Energy Of Mixing ◽  
Equilibrium Data ◽  
Gibbs Energy Of Mixing ◽  
Corrosion Mechanisms

Understanding the corrosion mechanisms and the effect of corrosion products on the basic properties of the salt (e.g., melting point, heat capacity) is fundamental for the safety assessment and durability of molten salt reactor technology. This work focused on the thermodynamic assessment of the CrF2−CrF3 system and the binary systems of chromium trifluoride CrF3 with alkali fluorides (LiF, NaF, KF) using the CALPHAD (computer coupling of phase diagrams and thermochemistry) method. In this work, the modified quasi-chemical model in the quadruplet approximation was used to develop new thermodynamic modelling assessments of the binary solutions, which are highly relevant in assessing the corrosion process in molten salt reactors. The agreement between these assessments and the phase equilibrium data available in the literature is generally good. The excess properties (mixing enthalpies, entropies and Gibbs energies) calculated in this work are consistent with the expected behaviour of decreasing enthalpy and Gibbs energy of mixing with the increasing ionic radius of the alkali cations.

Combinatorial Entropy of Mixing for Molecules Differing in Size and Shape

1973 ◽  
Vol 51 (18) ◽  
pp. 3071-3080 ◽  
Author(s):  
Rüdiger N. Lichtenthaler ◽  
Denis S. Abrams ◽  
John M. Prausnitz
Keyword(s):  
Molecular Size ◽  
Molecular Shape ◽  
Chain Polymer ◽  
Entropy Of Mixing ◽  
Size And Shape ◽  
Energy Of Mixing ◽  
Equilibrium Data ◽  
Gibbs Energy Of Mixing ◽  
Leading Term ◽  
Simple Evaluation

In reducing experimental vapour–liquid equilibrium data it is common to calculate the Gibbs energy of mixing in excess of that for a solution whose entropy of mixing is given by one of two expressions; ideal entropy or Flory–Huggins entropy. The first of these is proper for a mixture of small molecules of similar size and the second one is proper for a mixture of monomer and chain polymer. This paper considers intermediate cases where there are significant differences in molecular shape as well as size. An expression is derived for the combinatorial entropy of mixing; this expression has Flory's result as the leading term but also contains corrections for molecular bulkiness. The combinatorial entropy of mixing depends on characteristic parameters reflecting both molecular size and shape. Methods are given for simple evaluation of these parameters and illustrations for representative mixtures are presented. In some case, the corrections for bulkiness can be very large.

Liquid-Vapour Equilibria. X. The Systems Acetone+Nitromethane and Acetone+Acetonitrile at 45°C

1960 ◽  
Vol 13 (1) ◽  
pp. 30 ◽  
Author(s):  
I Brown ◽  
F Smith
Keyword(s):  
Free Energy ◽  
Experimental Error ◽  
Binary Systems ◽  
Virial Coefficient ◽  
Excess Free Energy ◽  
Specific Interaction ◽  
A Value ◽  
Energy Of Mixing ◽  
Equilibrium Data ◽  
Free Energy Of Mixing

Liquid-vapour equilibrium data are given for the systems acetone+nitromethane and acetone+acetonitrile at 45.00 �C. The data are used to calculate the excess free energy of mixing for these systems. The former system has a negative value of the excess free energy of mixing and shows a change in sign of the deviation of the activity of nitromethane from the Raoults law value at a mole fraction of acetone of 0.36. A value of the virial coefficient β12 in the equation of state of the mixed vapours was estimated from the equilibrium data for this system. The excess free energy of mixing for the system acetone+acetonitrile is zero within the experimental error over the whole concentration range. The Stockmayer potential was used to calculate values of β12, for the binary systems formed from acetone, nitromethane, and acetonitrile. For the system acetone+nitromethane the value estimated from our data is more negative than the value calculated using the Stockmayer potential, indicating a specific interaction, possibly hydrogen bonding, between the acetone and nitromethane molecules.

scholarly journals Isobaric Vapor−Liquid Equilibrium Data and Excess Properties of Binary Systems Comprised of Alkyl Methanoates + Hexane

2007 ◽  
Vol 52 (1) ◽  
pp. 215-225 ◽  
Author(s):  
Juan Ortega ◽  
Gisela Sabater ◽  
Ignacio de la Nuez ◽  
Juan J. Quintana ◽  
Jaime Wisniak
Keyword(s):  
Binary Systems ◽  
Excess Properties ◽  
Liquid Equilibrium ◽  
Vapor Liquid Equilibrium ◽  
Equilibrium Data ◽  
Vapor Liquid

Vapour-Liquid Equilibria and Excess Thermodynamic Properties in Binary Systems of Cyclopentanone + Chloroalkanes in View of the Disquac and Unifac Group Contribution Models Extention

2008 ◽  
Vol 59 (5) ◽  
Author(s):  
Alexandru Birhala ◽  
Dana Dragoescu ◽  
Mariana Teodorescu
Keyword(s):  
Binary Systems ◽  
Excess Enthalpy ◽  
Group Contribution ◽  
Excess Properties ◽  
Structural Effects ◽  
Liquid Equilibrium ◽  
Excess Thermodynamic Properties ◽  
Different Types ◽  
Thermodynamic Excess Properties ◽  
Thermodynamic Excess

The data available in the literature and our recent data on vapour�liquid equilibrium (VLE), excess Gibbs energy, GE, and excess enthalpy, HE, for the homologous series of cyclopentanone + chloroalkane mixtures are examined in terms of the predictive group contribution models DISQUAC and UNIFAC. In our treatment, we present also how the structural effects and different types of molecular interactions are reflected by the thermodynamic excess properties of the mentioned series mixtures.

Activities of Components in the Ca2MgSi2O7-CaSiO3Molten System

1996 ◽  
Vol 61 (6) ◽  
pp. 837-843
Author(s):  
Ladislav Kosa ◽  
Ivan Nerád ◽  
Katarína Adamkovičová ◽  
Jozef Strečko ◽  
Ivo Proks
Keyword(s):  
Gibbs Energy ◽  
Molar Mass ◽  
Excess Entropy ◽  
Enthalpy Of Mixing ◽  
Real Particle ◽  
Entropy Of Mixing ◽  
Energy Of Mixing ◽  
Gibbs Energy Of Mixing

Activities of the components, the Gibbs energy of mixing, and the excess entropy of mixing have been calculated for the Ca2MgSi2O7-CaSiO3 system. The mole fractions of the components were calculated assuming that in the point of the formal component Ca2MgSi2O7, the molar mass of the quasi-real particle in the melt corresponds to its formula molar mass, whereas in the point of the formal component CaSiO3 the molar mass of the quasi-real particle in the melt is 8.5 times higher than as corresponds to its formula. The fact that the enthalpy of mixing is zero whereas the excess entropy of mixing is non-zero suggests that Ca2MgSi2O7-CaSiO3 melts behave as athermal solutions.

Thermodynamic assessment of B–Zr and Si–Zr binary systems

2009 ◽  
Vol 468 (1-2) ◽  
pp. 209-216 ◽  
Author(s):  
H.M. Chen ◽  
F. Zheng ◽  
H.S. Liu ◽  
L.B. Liu ◽  
Z.P. Jin
Keyword(s):  
Binary Systems ◽  
Thermodynamic Assessment

Calculation of phase diagrams and thermodynamic properties of 14 additive and reciprocal ternary systems containing Li2CO3, Na2CO3, K2CO3, Li2SO4, Na2SO4, K2SO4, LiOH, NaOH, and KOH

1984 ◽  
Vol 62 (3) ◽  
pp. 457-474 ◽  
Author(s):  
A. D. Pelton ◽  
C. W. Bale ◽  
P. L. Lin
Keyword(s):  
Phase Diagram ◽  
Thermodynamic Properties ◽  
Molten Salt ◽  
Phase Diagrams ◽  
Binary Systems ◽  
Ternary Phase ◽  
Ternary Phase Diagram ◽  
Ternary Systems ◽  
Maximum Error ◽  
Critical Assessment

Phase diagrams and thermodynamic properties of five additive molten salt ternary systems and nine reciprocal molten salt ternary systems containing the ions Li+, Na+, [Formula: see text], OH− are calculated from the thermodynamic properties of their binary subsystems which were obtained previously by a critical assessment of the thermodynamic data and the phase diagrams in these binary systems. Thermodynamic properties of ternary liquid phases are estimated from the binary properties by means of the Conformal Ionic Solution Theory. The ternary phase diagrams are then calculated from these thermodynamic properties by means of computer programs designed for the purpose. It is found that a ternary phase diagram can generally be calculated in this way with a maximum error about twice that of the maximum error in the binary phase diagrams upon which the calculations are based. If, in addition, some reliable ternary phase diagram measurements are available, these can be used to obtain small ternary correction terms. In this way, ternary phase diagram measurements can be smoothed and the isotherms drawn in a thermodynamically correct way. The thermodynamic approach permits experimental data to be critically assessed in the light of thermodynamic principles and accepted solution models. A critical assessment of error limits on all the calculated ternary diagrams is made, and suggestions as to which composition regions merit further experimental study are given.

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