Vapor pressures o aqueous melts. Lithium nitrate-potassium nitrate-water at 119-150.deg.

Tripp, Terrance B.; Braunstein, J.

doi:10.1021/j100726a056

Cited by 28 publications

(16 citation statements)

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“…•, x * (LiNO 3 ) = 0.60; •, x * (LiNO 3 ) = 0.65; +, x * (LiNO 3 ) = 0.70 from Tripp and Braunstein. (9) are of similar magnitude to those for the experimental data, which are also shown on the plot. This gives confidence in the functional forms chosen for the ternary parameters.…”

Section: Applicationssupporting

confidence: 73%

“…The water activities determined by Simonson and Pitzer (8) from water vapour pressure measurements were taken from their table I. Equilibrium water vapour pressures measured by Tripp and Braunstein (9) were converted to water activities by using vapour pressures of pure water calculated from the equation of state of Hill, (10) and neglecting fugacity corrections (thus a w = p w / p o w ). Water activities were calculated from the isopiestic molalities determined by Braunstein and Braunstein (11) with water activities from Simonson and Pitzer (8) {for x * (LiNO 3 ) = 0.5034} and Tripp and Braunstein (9) {for x * (LiNO 3 ) = 0.500} as standards. In these calculations, the small differences in solute composition {0.0034 in x * (LiNO 3 )} and temperature ( T ≈ 1.25 K) were ignored.…”

Section: Applicationsmentioning

confidence: 99%

“…The results are shown in figure 1, both as water activity against the water mole fraction (calculated by assuming complete dissociation of the salts), and in a form linearised according to the BET relationship in equation (17) and using the definition of x w given after equation (21). Water activities for (8) 393.36 to 393.96 0.5034 Simonson and Pitzer (8) 393.25 1.0 Braunstein and Braunstein (11) 393.25 0.5034 Braunstein and Braunstein (11) 392.15 0.4500 Tripp and Braunstein (9) 392.15 0.5000 Tripp and Braunstein (9) 392.15 0.5500 Tripp and Braunstein (9) 392.15 0.6000 Tripp and Braunstein (9) 392.15 0.6500 Tripp and Braunstein (9) 392.15 0.7000 Tripp and Braunstein (9) a The range of results listed here is only a subset of those presented by these sources. The results for x * (LiNO 3 ) = 0.5034 and x * = 0.500 (both assumed to be 0.500) have also been fitted directly by using equation (17), treating the two solutes as a single combined salt s. The fit was restricted to water activities below 0.75, and gave parameters r s = 1.848 and c s = 2.304.…”

Section: Applicationsmentioning

confidence: 99%

“…We have also tested the expressions for mixture effects {equations Tripp and Braunstein (9) {see inset in part (b) for other data from these authors}; -, fitted values for the two pure salts and for mixture with n(LiNO 3 )/n(KNO 3 ) = 1 obtained by using equation (16) and the parameters given in the text. Here the water mole fraction x w was calculated by assuming complete dissociation of the salts.…”

Section: Applicationsmentioning

confidence: 99%

“…The parameter values are listed in the notes to table 2, and the fits for the binary •, x * (LiNO 3 ) = 0.5034 from Braunstein and Braunstein; (11) •, x * (LiNO 3 ) = 0.5034 from Simonson and Pitzer; (8) , x * (LiNO 3 ) = 0.50 from Tripp and Braunstein. (9) ---, predicted by using the model with binary (pure solution) parameters only; . .…”

Section: Applicationsmentioning

confidence: 99%

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A BET model of the thermodynamics of aqueous multicomponent solutions at extreme concentration

Clegg

Simonson

2001

The Journal of Chemical Thermodynamics

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Section: Applicationssupporting

confidence: 73%

Section: Applicationsmentioning

confidence: 99%

Section: Applicationsmentioning

confidence: 99%

Section: Applicationsmentioning

confidence: 99%

Section: Applicationsmentioning

confidence: 99%

See 3 more Smart Citations

A BET model of the thermodynamics of aqueous multicomponent solutions at extreme concentration

Clegg

Simonson

2001

The Journal of Chemical Thermodynamics

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Local composition model for excess Gibbs energy of electrolyte systems. Part I: Single solvent, single completely dissociated electrolyte systems

Chen¹,

Britt²,

Boston³

et al. 1982

AIChE Journal

845

481

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An electrolyte local composition model is developed for excess Gibbs energy, which is assumed to be the sum of two contributions, one resulting from long range electrostatic forces between ions and the other from short range forces between all the species. The validity of the model is demonstrated for systems emcompassing the entire range from molecular liquid to fused salt. and Cruz and Renon (1978). Of these, the Pitzer equation is especially useful. It has been applied successfully to represent data within experimental error from dilute solutions up to an ionic strength of six molal for both aqueous single strong electrolyte systems (Pitzer and Mayorga, 1973) and aqueous mixed strong electrolyte systems (Pitzer and Kim, 1974). Modified forms of the Pitzer equation have been used by Beutier and Renon (1978) and Edwards et al. (1978) as models for the ionic activity coefficients of aqueous weak electrolyte systems. The Pitzer equation was later extended (Chen et al., 1979) in a thermodynamically consistent manner to allow for molecular as well as ionic solutes in the aqueous systems. CHAU-CHYUN CHENPitzer's excess Gibbs energy equation is a virial expansion equation and is subject to all of the limitations of a virial model. The model parameters are arbitrary, temperaturedependent, and characteristic of the solvent. Binary parameters are empirical functions of ionic strength and ternary parameters are necessary at high ionic strength. The Pitzer equation can not be used for mixed solvent systems because its parameters are unknown functions of solvent composition. Therefore, although the Pitzer equation has been shown to be a convenient and accurate representation of aqueous electrolyte systems, a more versatile model is needed.In this study a new model is developed that does not have the disadvantages of a virial expression and that is applicable to a wide variety of electrolyte systems over the entire range of electrolyte concentrations and system temperatures. The kinds of systems that have been studied using the new model involve mixed electrolytes, mixed solvents, and partially dissociated electrolytes (Chen, 1980; Chen et al., 1980). It is anticipated that the model is also applicable to systems involving salt precipitation, immiscible liquid phases, and fused salt solutions. However, this paper, part one of a series, is limited to single solvent, single completely dissociated electrolyte systems in order to emphasize the model development, the physical interpretation of the model parameters, and the two critical assumptions on which the model is based. In part two of the series (Chen et al., 1982) the model is extended to multicomponent systems, including partially dissociated electrolytes which involve dissociation equilibria. CONCLUSIONS AND SIGNIFICANCEA new model has been developed for the excess Gibbs energy of electrolyte systems. It is based on the local composition concept and is designed to represent the properties of all kinds of electrolyte systems over the entire range of electrolyte concentra...

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A unified approach for prediction of thermodynamic properties of aqueous mixed‐electrolyte solutions. Part I: Vapor pressure and heat of vaporization

Patwardhan

Kumar

1986

AIChE Journal

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The overall nonideality of an aqueous mixed electrolyte solution is characterized in terms of a newly defined parameterr*, called the overall reduced ionic activity coefficient. It is shown that I ' * for the mixed solution is simply related to the properties of single-electrolyte solutions. r* is related to the vapor pressure of a mixed-electrolyte solution through well-known thermodynamic equations. This leads to a predictive equation for the vapor pressure of a mixed-electrolyte solution in terms of the vapor pressures of single-electrolyte solutions of the components. This equation is valid over the entire concentration range encountered in practice, without any empirical constants, and has a predictive accuracy of 2%. A predictive equation for the latent heat of vaporization is also developed and tested against experimental data. V. S. Patwardhan, Anil Kumar Chemical Engineering Division National Chemical LaboratoryPune 4 1 1 008. India SCOPEThe thermodynamic properties of aqueous mixedelectrolyte solutions play an important role in several areas, such as design of absorption heat pumps, general-purpose property packages for process simulators, water desalination, and oil recovery. Such properties include the vapor pressure, latent heat of vaporization, volume properties such as density and compressibility, thermal properties such as enthalpy and specific heat, and free energy. These properties have been extensively reported in the literature for aqueous solutions of single electrolytes. Predictive methods that can make use of this information and predict the properties of mixed solutions even for concentrated solutions obviously have tremendous practical utility.Theoretical approaches available for understanding aqueous electrolyte solutions are usually limited to Correspondence concerning this paper should be addressed to V. S. Patwardhan rather dilute solutions and are cumbersome for numerical calculations. Semiempirical approaches overcome these limitations, but need several adjustable parameters based on specific experimental data. The present study was aimed at developing simple but sufficiently accurate predictive equations for the thermodynamic properties of aqueous mixed-electrolyte solutions. In this paper, we restrict our attention to vapor pressures and heats of vaporization. In the case of a single electrolyte solution, the nonideality is represented in terms of the mean ionic activity coefficient, which is related to the vapor pressure. A generalization of this for mixed-electrolyte solutions leads to the newly defined overall ionic activity coefficient, which is related to the vapor pressure of such solutions. Making use of these, and a proposed relationship between the overall ionic activity coefficient and the mean ionic activity coefficients for single-electrolyte solutions, predictive equations are derived for the vapor pressure and the heat of vaporization for mixed-electrolyte sotutions.

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Vapor pressures o aqueous melts. Lithium nitrate-potassium nitrate-water at 119-150.deg.

Cited by 28 publications

References 6 publications

A BET model of the thermodynamics of aqueous multicomponent solutions at extreme concentration

A BET model of the thermodynamics of aqueous multicomponent solutions at extreme concentration

Local composition model for excess Gibbs energy of electrolyte systems. Part I: Single solvent, single completely dissociated electrolyte systems

A unified approach for prediction of thermodynamic properties of aqueous mixed‐electrolyte solutions. Part I: Vapor pressure and heat of vaporization

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