DISQUAC predictions on thermodynamic properties of ternary and higher multicomponent mixtures. II. Results for HE of ternary mixtures containing nonpolar components, or one polar compound, two polar compounds, or one alcohol and hydrocarbons, or CCl4

2001 ◽  
Vol 79 (10) ◽  
pp. 1447-1459 ◽  
Author(s):  
Juan Antonio Gonzalez ◽  
Javier Carmona ◽  
Nicolas Riesco ◽  
Isaias Garcia de la Fuente ◽  
Jose Carlos Cobos

The ability of the DISQUAC model for predicting excess enthalpies (HE) of ternary systems on the basis of binary parameters only, i.e., neglecting ternary interactions is analyzed. At this end, DISQUAC results for a set of 95 ternary systems are examined. The solutions studied are formed by only hydrocarbons (or CCl4); or by one polar compound (not alcohols) and two hydrocarbons (or CCl4); or by two polar compounds (not alcohols) and one hydrocarbon (or CCl4); or by one alcohol and two hydrocarbons (or CCl4). Most of the HEs analyzed are endothermic, and valid at 298.15 K and atmospheric pressure. The mean deviation between experimental values and DISQUAC results is 5.5% for the ternary systems and 6.5% for the constituent binaries (181 mixtures). The interaction parameters used are valid for the description of thermodynamic properties of binary systems: vapor–liquid equilibria (VLE), liquid–liquid (LLE), and solid–liquid equilibria (SLE), HE and excess heat capacities at constant pressure (CEP), as well as HE and VLE of ternary solutions. Predictions are, in most of the cases, independent of the mixture compounds, or the number of groups present in the system. Larger deviations underline typical shortcomings of the group contributions methods (e.g., Patterson's effect; branching). Note that results for the ternaries and for the constituent binaries are of the same order. This is not the case for the Dortmund version of UNIFAC. The mean deviations obtained using this model are 10.5% and 14% for the ternary and binary mixtures, respectively. Results from other models (original UNIFAC, Flory's theory, Nitta–Chao, UNIQUAC association model) for a number of systems are also compared to those obtained using DISQUAC.Key words: predictions, HE, ternary systems, binary parameters, geometrical methods, Flory, group contributions.

2005 ◽  
Vol 83 (10) ◽  
pp. 1812-1825 ◽  
Author(s):  
Juan Antonio González ◽  
Ismael Mozo ◽  
Isaías García de la Fuente ◽  
José Carlos Cobos

Binary mixtures of aniline with benzene, toluene, alkane, alkanol, or N,N-dialkylamide have been investigated in the framework of the DISQUAC model. The reported interaction parameters change regularly with the molecular structure of the mixture components. The model consistently describes a set of thermodynamic properties including liquid–liquid equilibria, vapor–liquid equilibria, and molar excess enthalpies. The two latter properties for ternary systems are well-represented by DISQUAC using binary parameters only (i.e., neglecting ternary interactions). A comparison of DISQUAC results and those obtained from the UNIFAC (Dortmund version) and ERAS models is also shown. The experimental molar excess enthalpies for binary and ternary mixtures are better described by DISQUAC than by UNIFAC. ERAS fails when representing molar excess enthalpies of those binary systems including methanol or ethanol. This may be due to the existence of strong dipolar interactions among aniline molecules as well as to effects related to the equation of state term, evaluated comparing molar excess enthalpies, and molar excess internal energies at constant volume. The study of the aniline systems in terms of the concentration–concentration structure factor also underlines the importance of dipolar interactions in solutions with alkanes or alcohols, which may be due to the high polarizability of the aniline molecule.Key words: thermodynamics, mixtures, aniline, dipolar interactions, structural effects.


1984 ◽  
Vol 62 (3) ◽  
pp. 457-474 ◽  
Author(s):  
A. D. Pelton ◽  
C. W. Bale ◽  
P. L. Lin

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.


2017 ◽  
Vol 898 ◽  
pp. 1036-1041
Author(s):  
M.H. Rong ◽  
S.D. Lin ◽  
Jiang Wang ◽  
H.Y. Zhou ◽  
G.H. Rao

Ternary intermetallic compounds with rare earth elements and transition metals in the RE-Mn-X (X=Si, Ge, Sn etc.) ternary systems show interesting magnetic properties. As key sub-binary systems of the RE-Mn-X (X=Si, Ge, Sn etc.) ternary systems, the information of phase equilibria and thermodynamic properties of the Mn-RE (RE=Nd, Gd, Dy) binary systems are indispensable to explore the RE-Mn-X (X=Si, Ge, Sn etc.) alloys with better magnetic properties. In this work, the experimental data of phase equilibria and thermodynamic properties of the Mn-RE (RE=Nd, Gd, Dy) binary systems in the published literature were reviewed. Based on the available experimental information, thermodynamic calculation of phase equilibria of the Mn-RE (RE=Nd, Gd, Dy) binary systems was performed using the CALPHAD method. As a result, further experimental investigation and thermodynamic optimization would be still necessary in order to develop the self-consistent and compatible thermodynamic database of the RE-Mn-based alloy systems.


Author(s):  
N. Kotova ◽  
N. Usenko ◽  
N. Golovata

The features of the component interaction in liquid alloys of ternary Al-Ge-3d-Me systems (Me = Mn, Fe, Ni, Cu) are described. A joint analysis of the concentration dependences of the enthalpies of mixing of liquid alloys previously obtained by the authors via high-temperature calorimetry, and also of the phase diagrams of the constituent binary systems was carried out. The relationship between the enthalpy values and the type of short-range ordering in liquid alloys of the studied systems was established. The visual similarity of the topology of the projections of ΔmH isolines of the Al-Ge-Fe (Ni, Cu) liquid alloys and a completely different course of the isolines of the enthalpies of mixing for the liquid Al-Ge-Mn alloys are established. The changes in the absolute values of the ΔmHmin from system to system are observed. The enthalpies are approximately the same for the Al-Ge-Mn and Al-Ge-Fe systems (about -20 kJ⋅mol-1), they increase significantly from Al-Ge-Fe to Al-Ge-Ni (-50 kJ⋅mol-1), and then decrease substantially towards the Al-Ge-Cu system (-15 kJ⋅mol-1). For the Al-Ge-Mn (Fe, Ni, Cu) liquid alloys the lines of extreme interaction are located near the 3d-corner of the concentration triangle. These lines connect the compositions of the most stable intermetallic compounds in binary Al(Ge)-Mn(Fe, Ni, Cu) systems. It has been shown that the thermodynamic properties of Al-Ge-Fe (Ni, Cu) liquid alloys are mainly determined by the pair interaction of the components of the constituent binary Al-Fe(Ni, Cu) and Ge-Fe(Ni, Cu) systems, the influence of Al-Fe(Ni, Cu) systems being prevailed. For the Al-Ge-Mn system, the interaction of components in the Ge-Mn binary system gives the main contribution to the thermodynamic properties of the ternary system. The Al-Ge-Mn (Fe, Cu) systems are characterized by significantly lower absolute values of the heats of alloy formation compared to the Al-Ge-Ni one. The specified characteristics of component interaction in the ternary systems under consideration and different values of the enthalpies of mixing are determined by the peculiarities and regular changes of the electronic structure of 3d metals across the 3d series from Mn to Cu.


2020 ◽  
Vol 56 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Z.-G. Yu ◽  
H.-Y. Leng ◽  
L.-J. Wang ◽  
K. Chou

Refining slags is widely used in the production of high-value-added alloys and special steels. The removal of impurities depends on the mass transfer between the slag-metal interface, and the carbide capacity of the refining slags is crucial to control the carbon content in the final products. A phenomenological model is introduced in this article for the calculation of carbide capacity of different CaO-based ternary refining slags. The contour lines of carbide capacity in CaO-Al2O3- CaF2, CaO-SiO2-CaF2 CaO-SiO2-MnO systems are calculated based on limited experimental data by the present model. The experimental data within the calculation boundary are compared with the predicted values and satisfactory agreements are observed with the mean deviation being 1.4%, 2.3%, and 1.6%, for these three systems respectively. The present model is powerful and flexible in the calculation of carbide capacity of CaO-based ternary refining slags and can be applied to other systems.


2017 ◽  
Vol 898 ◽  
pp. 1042-1047
Author(s):  
M.H. Rong ◽  
X.L. Chen ◽  
Jiang Wang ◽  
S.D. Lin ◽  
G.H. Rao ◽  
...  

The experimental data of phase equilibria and thermodynamic properties of the Fe-RE (RE=Ho, Er, Tm, Sm) binary systems were reviewed. The previous thermodynamic calculation of the Fe-RE (RE=Ho, Er, Tm, Sm) binary systems were discussed based on the comparison of the calculated phase diagram and thermodynamic properties with the experimental data. The compared results show that more experimental information of phase diagram and thermodynamic properties in the Fe-RE (RE=Ho, Er, Tm, Sm) binary systems should be determined and then thermodynamic re-calculation of these binary systems would be performed to develop compatible and available thermodynamic database of the RE-Fe-B ternary systems. It is indispensable to study the relations between alloy compositions, microstructure and magnetic properties of novel Nd-Fe-B-based permanent magnets.


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