Abstract

The heat capacity of poly(lactic acid) (PLA) is reported from T=(5 to 600) K as obtained by differential scanning calorimetry (d.s.c.) and adiabatic calorimetry. The heat capacity of solid PLA is linked to its group vibrational spectrum and the skeletal vibrations, the latter being described by a Tarasov equation with Θ₁=574 K, Θ₂=Θ₃=52 K, and nine skeletal vibrations. The calculated and experimental heat capacities agree to ±3% between T=(5 and 300) K. The experimental heat capacity of liquid PLA can be expressed by C_p(liquid)=(120.17+0.076T) J · K⁻¹ · mol⁻¹ and has been compared to the ATHAS Data Bank, using contributions of other polymers with the same constituent groups. The glass transition temperature of amorphous PLA occurs at T=332.5 K with a change in heat capacity of 43.8 J · K⁻¹ · mol⁻¹. Depending on thermal history, semi-crystalline PLA has a melting endotherm between T=(418 and 432) K with variable heats of fusion. For 100% crystalline PLA, the heat of fusion is estimated to be (6.55 ± 0.02) kJ · mol⁻¹ at T=480 K. With these results, the enthalpy, entropy, and Gibbs function of crystalline and amorphous PLA were obtained. For semi-crystalline samples, one can check changes of crystallinity with temperature and judge the presence of rigid-amorphous fractions.

Author Keywords: Heat capacity; Poly(lactic acid); Heats of fusion; Glass transition; Melting; Crystallinity; Rigid-amorphous fraction

Article Outline

1. Introduction

1.1. Calculation of the heat capacity of the solid state

1.2. Heat capacity of the liquid state

2. Experimental

2.1. Samples

2.2. Instrumentation and measurements

3. Results and preliminary discussion

3.1. Heat capacity of solid and liquid PLA

3.2. Quantitative thermal analysis of PLA

4. Discussion

Acknowledgements

References

(4K)
FIGURE 1. Experimental d.s.c. curves as heat flow rate plotted against temperature on heating at 20 K · min⁻¹ of semi-crystalline PLA-L and amorphous PLA-M and PLA-H. All three samples were quickly cooled from the melt and kept isothermally at T=418.15 K (145 °C) for 15 h for development of crystallinity. The curves are shifted by an arbitrary amount for clarity.

(4K)
FIGURE 2. Experimental d.s.c. curves as heat flow rate plotted against temperature on heating at 20 K · min⁻¹ (a) of PLA-L quenched from the melt, and (b) of semi-crystalline PLA-L after isothermal crystallization at T=418.15 K (145 °C) for 15 h, as in figure 1. The curves are shifted by an arbitrary amount for clarity.

(6K)
FIGURE 3. Heat capacities plotted against temperature by d.s.c. for PLA-L samples cooled from the melt at 10 K · min⁻¹ and reheated with different heating rates from (30 to 0.3) K · min⁻¹. The curves are shifted in C_p for clarity.

(4K)
FIGURE 4. Experimental heat capacities of poly(lactic acid) plotted against temperature. The low-temperature data from T=(5 to 300) K are by adiabatic calorimetry as described in [9], The high-temperature data are by standard d.s.c. for PLA-L and PLA-H from T=(300 to 520) K after being isothermally crystallized at T=418.15 K for 15 h, from data as shown in figure 2.

(10K)
FIGURE 5. Fitting of the Θ-temperatures of PLA using the recommended C_p(exp) from T=(5 to 200) K (see table 1). The minimum in ² has an RMS error in C_p of ±3%.

(5K)
FIGURE 6. Experimental and calculated heat capacities of solid poly(lactic acid) plotted against temperature assuming only vibration motions according to the ATHAS (see the parameters for the calculation in table 4).

(6K)
FIGURE 7. Experimental and calculated heat capacities of solid and liquid PLA plotted against temperature, compared with experimental data on semi-crystalline PLA-L after isothermal crystallization at T=418.15 K (145 °C) for 15 h. The upper heavy solid line indicates the heat capacity of 100% amorphous PLA, as given by equation (12). The lower heavy line, the vibrational heat capacity of solid PLA (100% crystalline or glassy amorphous). The thin line represents the semi-crystalline C_p calculated from the crystallinity, known from the measured heat of fusion.

(4K)
FIGURE 8. Plot of ΔC_p at T_g plotted against temperature ΔH_fus for samples of PLA-L with different fractions of crystallinity. The arrow points to the extrapolated heat of fusion for a fully crystalline sample, as expected at an equilibrium melting temperature of T=480 K.

(4K)
FIGURE 9. Plot of the fractional degree of crystallinity against temperature, calculated for the samples of figure 2, using equation (13) and considering the temperature dependence of the heat capacities as given in table 1.

(5K)
FIGURE 10. Enthalpy (H−H_o^c) Gibbs free energy (G−H_o^c), and entropy contribution (TS) for poly(lactic acid) using the C_p(vibration) of table 2 and C_p(liquid) of equation (12).

TABLE 1. Measured and calculated heat capacities of semi-crystalline and amorphous PLA

TABLE 2. Number of group and skeletal modes of vibration in PLAa

TABLE 3. Group vibrations of COO– and CHCH₃–

TABLE 4. Results of the Θ₁, Θ₂, Θ₃ parameter determination for PLAa

References

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Corresponding author. Tel.: +1-865-974-0652

*1 The submitted manuscript has been authored by a contractor of the US Government under the contract No. DE-AC05-96OR22464. Accordingly, the US Government retains a non-exclusive, royalty-free license to publish, or reproduce the published form of this contribution, or allow others to do so, for US Government purposes.

Abstract

The densities of (o-xylene, or m-xylene, or p-xylene + dimethyl sulfoxide) were measured at temperatures (293.15, 303.15, 313.15, 323.15, 333.15, 343.15, 353.15) K and atmospheric pressure by means of a vibrating-tube densimeter. The excess molar volume V_m^E calculated from the density data provide the temperature dependence of V_m^E in the temperature range of (293.15 to 353.15) K. The V_m^E results were correlated using the fourth-order Redlich–Kister equation, with the maximum likelihood principle being applied for the determination of the adjustable parameters. Also we have calculated partial molar volume and excess partial molar volumes of two components. It was found that the V_m^E in the systems studied increase with rising temperature.

Author Keywords: Dimethyl sulfoxide; o-Xylene; m-Xylene; p-Xylene; Binary mixture; Excess volume; Partial molar volume; Excess partial molar volume; Temperature dependence

Article Outline

1. Introduction

2. Experimental

2.1. Materials

2.2. Apparatus and procedure

3. Results

4. Discussion

5. Conclusion

References

(13K)
FIGURE 1. The excess molar volume of x_o-(CH₃)₂C₆H₄ + (1−x)DMSO at atmospheric pressure against mole fraction. At T=298.15 K, ; T=303 K, o; T=313 K, ; T=323 K, +; T=333 K, ×; T=343 K, ; T=353 K, .

(13K)
FIGURE 2. The excess molar volume of x_m-(CH₃)₂C₆H₄ + (1−x)DMSO at atmospheric pressure against mole fraction. At T=298.15 K, ; T=303 K, o; T=313 K, ; T=323 K, +; T=333 K, ×; T=343 K, ; T=353 K, .

(13K)
FIGURE 3. The excess molar volume of x_p-(CH₃)₂C₆H₄ + (1−x)DMSO at atmospheric pressure against mole fraction. At T=298.15 K, ; T=303 K, o; T=313 K, ; T=323 K, +; T=333 K, ×; T=343 K, ; T=353 K, .

TABLE 1. Densities at T=298.15 K and refractive index values n_D²⁰ of the pure components, and comparison with literature

TABLE 2. Excess molar volumes, densities, partial molar volumes and excess partial molar volumes of x_o-C₆H₄(CH₃)₂ + (1−x)DMSO at the temperature (293.15 to 353.15 K) and atmospheric pressure

TABLE 3. Excess molar volumes, densities, partial molar volumes and excess partial molar volumes of x_m-C₆H₄(CH₃)₂ + (1−x)DMSO at the temperature (293.15 to 353.15 K) and atmospheric pressure

TABLE 4. Excess molar volumes, densities, partial molar volumes and excess partial molar volumes x_p-C₆H₄(CH₃)₂ + (1−x)DMSO at the temperature (293.15 to 353.15 K) and atmospheric pressure

TABLE 5. The least-squares parameters, standard deviations, and extremum values extremum values

References

1. A. Riddick, W.B. Bunger and T.K. Sakano. Organic Solvents vol. II, Wiley, New York (1986).

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5. M.I. Davis. Chem. Soc. Rev. 22 (1993), pp. 127–134.

Corresponding author. Tel./fax: +86-0510-5863151

¹ Present address: Department of Chemistry, Shaoxing College of Arts and Sciences, Shaoxing, Zhejiang 312000, PR China.

Abstract

The standard (p^o=0.1 MPa) molar enthalpies of formation of the crystalline complexes bis[N-(N″,N″-diethylaminothiocarbonyl)benzamidinato]nickel(II), {Ni(datb)₂}, and bis[N-(N″,N″-diethylaminothiocarbonyl)-N^′-phenylbenzamidinato]nickel(II), {Ni(datpb)₂}, were determined, at T=298.15 K, by high precision solution-reaction calorimetry.

From the obtained results, the metal–ligand exchange enthalpies in the crystalline phase were derived. The enthalpy of a hypothetical metal–ligand exchange reaction in the crystalline phase was derived, thus allowing a discussion of the energetics of complexation in comparison with known crystal-structural parameters.

Author Keywords: Standard molar enthalpy of formation; N-(Diethylaminothiocarbonyl)benzamidines; Nickel(II)-complexes; Bis[N-(N″,N″-diethylaminothiocarbonyl)benzamidinato]nickel(II); Bis[N-(N″,N″-diethylaminothiocarbonyl)-N^′-phenylbenzamidinato]nickel(II); High precision solution-reaction calorimetry

Article Outline

1. Introduction

2. Experimental

2.1. Synthesis

2.2. Solution calorimetry

3. Results

4. Discussion

Acknowledgements

References

(5K)
FIGURE 1. Schematic structure of the bis[N-(diethylaminothiocarbonyl)benzamidinato]nickel(II)-complexes: (a) {Ni(datb)₂}=bis[N-(N″,N″-diethylaminothiocarbonyl)benzamidinato]nickel(II); (b) {Ni(datpb)₂}=bis[N-(N″,N″-diethylaminothiocarbonyl)-N^′-phenylbenzamidinato]nickel(II).

TABLE 1. Molar enthalpies of reaction and solution Δ_iH_m at T=298.15 K, for the study of the nickel(II) complexes Ni(Et₂NCSNCNRPh)₂ of the two N-(diethylaminothiocarbonyl)benzamidines (Et₂NCSNCNHRPh (Hdatb: R=H; Hdatpb: R=Ph)), using 1,4-dioxan/HCl 4.2 mol · dm⁻³ (75% v/v) as calorimetric solvent
Solvent: 120.0 cm³ dioxan/HCl 4.2 mol · dm⁻³ (75% v/v).


TABLE 2. Standard (p^o=0.1 MPa) molar enthalpies of reaction, Δ_rH_m^o, and enthalpies of formation in crystalline state, Δ_fH_m^o(cr), for the crystalline complexes at T=298.15 K

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Corresponding author. Tel.: +351-22-6082-821; fax: +351-22-6082-822

Abstract

Relative densities have been measured for acidified aqueous solutions of ytterbium perchlorate {Yb(ClO₄)₃} at approximately T=(348.15, 373.15, 398.15, and 423.15) K and p=(10.0, 20.0, and 30.0) MPa over the concentration range 0.01624m₂/(mol · kg⁻¹)  0.2531 using an optically coupled vibrating tube densimeter (OCVTD). Experimental apparent molar volumes have been calculated from the density measurements, and apparent molar volumes for the aqueous perchlorate salt have been calculated using Young's rule. The application of Young's rule requires apparent molar volumes for aqueous perchloric acid (HClO₄) solutions over extended temperature and pressure ranges. These values were calculated from densities for aqueous HClO₄ solutions that were measured using the OCVTD at the same temperatures and pressures as those used to investigate the density surface of the acidified aqueous Yb(ClO₄)₃ solutions.

The temperature, pressure, and composition surfaces of the apparent molar volumes for Yb(ClO₄)₃(aq) and HClO₄(aq) have been modelled using Pitzer ion-interaction equations. Apparent molar volumes at infinite dilution obtained from these models have been compared to those which can be calculated using the semi-empirical Helgeson, Kirkham, and Flowers equations of state. Values for the apparent molar volume at infinite dilution of the ytterbium trivalent cation have also been calculated using simple additivity principles.

Author Keywords: Densities; Elevated temperature and pressure; Perchloric acid; Ytterbium perchlorate

Article Outline

1. Introduction

2. Experimental

3. Apparent molar volumes

4. Single ion volumes

Acknowledgements

References

(6K)
FIGURE 1. A plot of the residuals obtained from the fit of equations ((6), (7) and (8)) to calculated apparent molar volumes against concentration for HClO₄(aq). o, residuals calculated using V_,3 values reported in this study; •, residuals calculated using V_,3 values reported in [9].

(7K)
FIGURE 2. A plot of the residuals obtained from the fit of equations (10), ((12), (13) and (14)) to calculated apparent molar volumes against concentration for Yb(ClO₄)₃(aq). o, residuals calculated using V_,2 values reported in this study; •, residuals calculated using V_,2 values reported in [2].

(15K)
FIGURE 3. (a) A plot of apparent molar volume at infinite dilution, V_,3, for HClO₄(aq) against temperature at p=0.1 MPa. Solid line calculated using equations reported in [4], dashed line calculated using equation (7). (b) A plot of apparent molar volume at infinite dilution, V_,3, for HClO₄(aq) against temperature at p=10 MPa. Solid line calculated using equations reported in [4], dashed line calculated using equation (7). (c) A plot of apparent molar volume at infinite dilution, V_,3, for HClO₄(aq) against temperature at p=20 MPa. Solid line calculated using equations reported in [4], dashed line calculated using equation (7). (d) A plot of apparent molar volume at infinite dilution, V_,3, for HClO₄(aq) against temperature at p=30 MPa. Solid line calculated using equations reported in [4], dashed line calculated using equation (7).

(15K)
FIGURE 4. (a) A plot of apparent molar volume at infinite dilution, V_,2, for Yb(ClO₄)₃(aq) against temperature at p=0.1 MPa. Solid line calculated using equations reported in [4], dashed line calculated using equation (12). (b) A plot of apparent molar volume at infinite dilution, V_,2, for Yb(ClO₄)₃(aq) against temperature at p=10 MPa. Solid line calculated using equations reported in [4], dashed line calculated using equation (12). (c) A plot of apparent molar volume at infinite dilution, V_,2, for Yb(ClO₄)₃(aq) against temperature at p=20 MPa. Solid line calculated using equations reported in [4], dashed line calculated using equation (12). (d) A plot of apparent molar volume at infinite dilution, V_,2, for Yb(ClO₄)₃(aq) against temperature at p=30 MPa. Solid line calculated using equations reported in [4], dashed line calculated using equation (12).

TABLE 1. The densities of pure water, ₁, the concentration dependence of relative densities, ₃−₁, apparent molar volumes of aqueous solutions of perchloric acid, V_,3, and the uncertainties in apparent molar volumes, V_,3, at approximately T=348.15 K and p=(10, 20 and 30) MPa

TABLE 2. The densities of pure water, ₁, the concentration dependence of relative densities, ₃−₁, apparent molar volumes of aqueous solutions of perchloric acid, V_,3, and the uncertainties in apparent molar volumes, V_,3, at approximately T=373.15 K and p=(10, 20 and 30) MPa

TABLE 3. The densities of pure water, ₁, the concentration dependence of relative densities, ₃−₁, apparent molar volumes of aqueous solutions of perchloric acid, V_,3, and the uncertainties in apparent molar volumes, V_,3, at approximately T=398.15 K and p=(10, 20 and 30) MPa

TABLE 4. The densities of pure water, ₁, the concentration dependence of relative densities, ₃−₁, apparent molar volumes of aqueous solutions of perchloric acid, V_,3, and the uncertainties in apparent molar volumes, V_,3, at approximately T=423.15 K and p=(10 and 20) MPa

TABLE 5. Estimates of fitting parameters to equations ((6), (7) and (8)) which model the temperature and pressure dependences of V_,3 values for aqueous solutions of perchloric acid

TABLE 6. The density of pure water, ₁, the concentration dependences of relative densities, _expt−₁, experimental apparent molar volumes, V_,expt, apparent molar volumes of Yb(ClO₄)₃(aq) solutions, V_,2, and their uncertainties, V_,2, at approximately T=348.15 K and p=(10, 20 and 30) MPa

TABLE 7. The density of pure water, ₁, the concentration dependences of relative densities, _expt−₁, experimental apparent molar volumes, V_,expt, apparent molar volumes of Yb(ClO₄)₃(aq) solutions, V_,2, and their uncertainties, V_,2, at approximately T=373.15 K and p=(10, 20 and 30) MPa

TABLE 8. The density of pure water, ₁, the concentration dependences of relative densities, _expt−₁, experimental apparent molar volumes, V_,expt, apparent molar volumes of Yb(ClO₄)₃(aq) solutions, V_,2, and their uncertainties, V_,2, at approximately T=398.15 K and p=(10, 20 and 30) MPa

TABLE 9. The density of pure water, ₁, the concentration dependences of relative densities, _expt−₁, experimental apparent molar volumes, V_,expt, apparent molar volumes of Yb(ClO₄)₃(aq) solutions, V_,2, and their uncertainties, V_,2, at approximately T=423.15 K and p=(10 and 20) MPa

TABLE 10. Estimates of the fitting parameters to equations (10), ((12), (13) and (14)) which model the temperature and pressure dependences of V_,2 values for Yb(ClO₄)₃(aq) solutions

TABLE 11. Estimates of values for V{Yb³⁺(aq)} obtained from equation (15) at selected temperatures and pressures

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21. C. Xiao and P.R. Tremaine. J. Chem. Thermodyn. 29 (1997), pp. 827–852.

22. J.W. Johnson and D. Norton. Am. J. Sci. 291 (1991), pp. 541–648.

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24. M.J. Lukacs, MSc Thesis, The University of Lethbridge, Alberta, Canada, 2003

Corresponding author. Tel.: +1-403-329-2083; fax: +1-403-329-2057

Abstract

Acidified aqueous solutions of Pr(ClO₄)₃(aq), Gd(ClO₄)₃(aq), Ho(ClO₄)₃(aq), and Tm(ClO₄)₃(aq) were prepared from the corresponding oxides by dissolution in dilute perchloric acid. Once characterized with respect to trivalent metal cation and acid content, the relative densities of the solutions were measured at T=(288.15, 298.15, 313.15, and 328.15) K and p=0.1 MPa using a Sodev O2D vibrating tube densimeter. The relative massic heat capacities of the aqueous systems were also determined, under the same temperature and pressure conditions, using a Picker Flow Microcalorimeter. All measurements were made on solutions containing rare earth salt in the concentration range 0.01  m/(mol · kg⁻¹)  0.2. Relative densities and relative massic heat capacities were used to calculate the apparent molar volumes and apparent molar heat capacities of the acidified salt solutions from which the apparent molar properties of the aqueous salt solutions were extracted by the application of Young's Rule. The concentration dependences of the isothermal apparent molar volumes and heat capacities of each aqueous salt solution were modelled using Pitzer ion-interaction equations. These models produced estimates of apparent molar volumes and apparent molar heat capacities at infinite dilution for each set of isothermal V_,2 and C_p,2 values. In addition, the temperature and concentration dependences of the apparent molar volumes and apparent molar heat capacities of the aqueous rare earth perchlorate salt solutions were modelled using modified Pitzer ion-interaction equations. The latter equations utilized the Helgeson, Kirkham, and Flowers equations of state to model the temperature dependences (at p=0.1 MPa) of apparent molar volumes and apparent molar heat capacities at infinite dilution. The results of the latter models were compared to those previously published in the literature.

Apparent molar volumes and apparent heat capacities at infinite dilution for the trivalent metal cations Pr³⁺(aq), Gd³⁺(aq), Ho³⁺(aq), and Tm³⁺(aq) were calculated using the conventions V₂^o(H⁺(aq)) ≡ 0 and C_p2^o(H⁺(aq)) ≡ 0 and have been compared to other values reported in the literature.

Author Keywords: Apparent molar volume; Apparent molar heat capacity; Density; Massic heat capacity; Rare-earth(III) perchlorates; Aqueous solutions

Article Outline

1. Introduction

2. Experimental

3. Results

4. Discussion

Acknowledgements

References

(5K)
FIGURE 1. A plot of apparent molar volume, V_,2, against the square root of the ionic strength, I^1/2, for aqueous solutions of Gd(ClO₄)₃ at T=(298.15, 313.15, and 328.15) K. •, Reference [6]; +, reference [15]; Δ, reference [16]; o, this study.

(6K)
FIGURE 2. A plot of {V_,2−6·(A_V/b)·ln(1+b·I^1/2)+Q} against ionic strength for aqueous solutions of Pr(ClO₄)₃. •, T=288.15 K; o, T=298.15 K; , T=313.15 K; , T=328.15 K. The solid lines represent the model fit of equations (6), ((8), (9) and (10)) to the experimental data.

(8K)
FIGURE 3. (a) A plot of apparent molar volume, C_p,2, against the square root of the ionic strength, I^1/2, for aqueous solutions of Gd(ClO₄)₃ at T=(298.15 and 328.15) K. •, reference [6]; o, this study. (b) A plot of apparent heat capacity, C_p,2, against the square root of the ionic strength, I^1/2, for aqueous solutions of Gd(ClO₄)₃ at T=(313.15) K. •, reference [6]; o, this study.

(5K)
FIGURE 4. A plot of {C_p,2−6·(A_J/b)·ln(1+b·I^1/2)−TX} against ionic strength for aqueous solutions of Pr(ClO₄)₃. •, T=288.15 K; o, T=298.15 K; , T=313.15 K; , T=328.15 K. The solid lines represent the model fit of equations ((11), (12), (13) and (14)) to the experimental data.

(5K)
FIGURE 5. Plots of apparent molar volume at infinite dilution, V₂^o, against ionic radii, r, for aqueous rare earth perchlorate salts at T=(288.15, 298.15, 313.15, and 328.15) K.

(5K)
FIGURE 6. Plots of apparent molar heat capacity at infinite dilution, C_p2^o, against ionic radii, r, for aqueous rare earth perchlorate salts at T=(288.15, 298.15, 313.15, and 328.15) K.

(4K)
FIGURE 7. A plot of V₂^o against temperature for solutions of Gd(ClO₄)₃(aq); •, values from [6]; o, values from table 5; (a) HKF equation using parameters obtained from [22]; (b) HKF model represented by equation (8).

(4K)
FIGURE 8. A plot of the intrinsic and solvation contributions to V₂^o against temperature for Ho(ClO₄)₃(aq); (a), the intrinsic contribution (₁ & ₂ terms of equation (8)); (b) HKF model represented by equation (8); (c) the solvation contribution (−Q term of equation (8)); o, experimental V₂^o values reported in table 5.

(4K)
FIGURE 9. A plot of the intrinsic and solvation contributions to C_p2^o against temperature for Ho(ClO₄)₃(aq); (a), the intrinsic contribution (c₁ & c₂ terms of equation (12)); (b) HKF model represented by equation (12); (c) the solvation contribution (TX term of equation (12)); o, experimental C_p2^o reported in table 5.

TABLE 1. The concentration dependences of relative densities, relative heat capacities, apparent molar volumes and apparent molar heat capacities for acidified aqueous solutions Pr(ClO₄)₃ at T=(288.15, 298.15, 313.15, and 328.15) K

TABLE 2. The concentration dependences of relative densities, relative heat capacities, apparent molar volumes and apparent molar heat capacities for acidified aqueous solutions Gd(ClO₄)₃ at T=(288.15, 298.15, 313.15, and 328.15) K

TABLE 3. The concentration dependences of relative densities, relative heat capacities, apparent molar volumes and apparent molar heat capacities for acidified aqueous solutions Ho(ClO₄)₃ at T=(288.15, 298.15, 313.15, and 328.15) K

TABLE 4. The concentration dependences of relative densities, relative heat capacities, apparent molar volumes and apparent molar heat capacities for acidified aqueous solutions Tm(ClO₄)₃ at T=(288.15, 298.15, 313.15, and 328.15) K

TABLE 5. Estimates of parameters to the Pitzer ion interaction model equations, shown as equations ((6) and (11)) within the text, for aqueous solutions of Pr(ClO₄)₃, Gd(ClO₄)₃, Ho(ClO₄)₃, and Tm(ClO₄)₃ at T=(288.15, 298.15, 313.15, and 328.15) K and p=0.1 MPa

TABLE 6. Comparison of calculated V₂^o values with those previously reported in the literature for aqueous solutions of Pr(ClO₄)₃, Gd(ClO₄)₃, Ho(ClO₄)₃, and Tm(ClO₄)₃ at selected temperatures and p=0.1 MPa

TABLE 7. Estimates of parameters to equations ((8), (9) and (10)) which model the temperature dependences of V_,2 values for aqueous solutions of Pr(ClO₄)₃, Gd(ClO₄)₃, Ho(ClO₄)₃, and Tm(ClO₄)₃ at p=0.1 MPa

TABLE 8. Comparison of calculated C_p2^o values with those previously reported in the literature for aqueous solutions of Pr(ClO₄)₃, Gd(ClO₄)₃, Ho(ClO₄)₃, and Tm(ClO₄)₃ at selected temperatures and p=0.1 MPa

TABLE 9. Estimates of parameters to equations ((12), (13) and (14)) which model the temperature dependences of C_p,2 values for aqueous solutions of Pr(ClO₄)₃, Gd(ClO₄)₃, Ho(ClO₄)₃, and Tm(ClO₄)₃ at p=0.1 MPa

TABLE 10. A comparison of literature and calculated V₂^o(R³⁺(aq)) and C_p2^o(R³⁺(aq)) values for R³⁺(aq)=(Pr³⁺(aq), Gd³⁺(aq), Ho³⁺(aq), and Tm³⁺(aq)) at T=(288.15, 298.15, 313.15, and 328.15) K and p=0.1 MPa

References

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23. F.J. Waller, A.G.M. Barrett, D.C. Braddock and D. Ramprasad. Chem. Commun. (1997), pp. 613–614.

Corresponding author. Tel.: +1-403-329-2083; fax: +1-403-329-2057

Abstract

The molar heat capacity C_p,m of 1-cyclohexene-1,2-dicarboxylic anhydride was measured in the temperature range from T=(80 to 360) K with a small sample automated adiabatic calorimeter. The melting point T_m, the molar enthalpy Δ_fusH_m and the entropy Δ_fusS_m of fusion for the compound were determined to be (343.46 ± 0.24) K, (11.88 ± 0.02) kJ · mol⁻¹ and (34.60 ± 0.06) J · K⁻¹ · mol⁻¹, respectively. The thermodynamic functions [H_(T)−H_(298.15)] and [S_(T)−S_(298.15)] were derived in the temperature range from T=(80 to 360) K with temperature interval of 5 K. The mass fraction purity of the sample used in the adiabatic calorimetric study was determined to be 0.9928 by using the fractional melting technique. The thermal stability of the compound was investigated by differential scanning calorimeter (DSC) and thermogravimetric (TG) technique, and the process of the mass-loss of the sample was due to the evaporation, instead of its thermal decomposition.

Author Keywords: 1-Cyclohexene-1,2-dicarboxylic anhydride; Adiabatic calorimeter; Low-temperature heat capacity; Purity determination; Thermal analysis

Article Outline

1. Introduction

2. Experimental

2.1. Sample

2.2. Adiabatic calorimetry

2.3. DSC and TG technique

3. Results and discussion

3.1. Molar heat capacity and thermodynamic functions

3.2. The purity determination of 3,4,5,6-THPA

3.3. The results of DSC and TG analysis

Acknowledgements

References

(8K)
FIGURE 1. Experimental molar heat-capacity plotted against temperature for the sample 3,4,5,6-THPA. The "" represents the first series of heat capacity measurement; "o", the second series of heat-capacity measurement and "", the third series of heat-capacity measurement.

(6K)
FIGURE 2. Plot of melting temperature against reciprocal mass fraction melted for 3,4,5,6-THPA.

(4K)
FIGURE 3. DSC curve of 3,4,5,6-THPA.

(4K)
FIGURE 4. TG-DTG curve of 3,4,5,6-THPA.

TABLE 1. Experimental molar heat capacities of 3,4,5,6-THPA (M=152.16 g · mol⁻¹) (R=8.314427 J · mol⁻¹ · K⁻¹)a

TABLE 2. The results of melting obtained from three series of heat capacity measurements of the sample

TABLE 3. The thermodynamic functions of 3,4,5,6-THPA (R=8.314427 J · mol⁻¹ · K⁻¹)a

TABLE 4. The experimental results of melting fractions and equilibrium temperatures of 3,4,5,6-THPA [F=q/(ΔH_m·n)]

References

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7. Y.-Y. Di, Z.-C. Tan, X.-H. Sun, M.-H. Wang et al.. J. Chem. Thermodyn. 36 (2004), pp. 79–86.

8. D.G. Archer. J. Phys. Chem. Ref. Data 22 (1993), pp. 1441–1452.

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12. J.M. Peter and N.T. Barry. J. Phys. Chem. Ref. Data 28 6 (1999), pp. 1713–1852.

Corresponding author. Fax: +86-411-469-1570

Abstract

A complete critical evaluation of all available phase diagram and thermodynamic data has been performed for all condensed phases of the (MgCl₂ + CaCl₂ + MnCl₂ + FeCl₂ + CoCl₂ + NiCl₂) system, and optimized model parameters have been found. The model parameters obtained for the binary subsystems can be used to predict thermodynamic properties and phase equilibria for the multicomponent system. The Modified Quasichemical Model was used for the molten salt phase, and the (MgCl₂ + MnCl₂ + FeCl₂ + CoCl₂ + NiCl₂) solid solution was modeled using a cationic substitutional model with an ideal entropy and an excess Gibbs free energy expressed as a polynomial in the component mole fractions. This is the first of two articles on the optimization of the (NaCl + KCl + MgCl₂ + CaCl₂ + MnCl₂ + FeCl₂ + CoCl₂ + NiCl₂) system.

Author Keywords: Molten chlorides; Transition metal chlorides; Hot corrosion; Thermodynamic modeling; Thermodynamic database

Article Outline

1. Introduction

2. Thermodynamic data for the pure compounds

3. Thermodynamic model for the liquid phase

4. Thermodynamic model for the solid solution

5. Binary systems

5.1. The (MgCl₂ + CaCl₂) system

5.2. The (MgCl₂ + MnCl₂) system

5.3. The (FeCl₂ + MgCl₂) system

5.4. The (CoCl₂ + MgCl₂) system

5.5. The (CaCl₂ + MnCl₂) system

5.6. The (FeCl₂ + CaCl₂) system

5.7. The (CaCl₂ + CoCl₂) system

5.8. The (FeCl₂ + MnCl₂) system

5.9. The (CoCl₂ + MnCl₂) system

5.10. The (FeCl₂ + CoCl₂) system

5.11. Binary systems involving NiCl₂

5.11.1. The (CaCl₂ + NiCl₂) system

5.11.2. The (CoCl₂ + NiCl₂) system

5.11.3. The (MnCl₂ + NiCl₂) system

5.11.4. The (FeCl₂ + NiCl₂) system

5.11.5. The (MgCl₂ + NiCl₂) system

6. Multicomponent systems

6.1. The (FeCl₂ + MgCl₂ + MnCl₂) system

6.2. The (CaCl₂ + MgCl₂ + MnCl₂) system

7. Discussion

8. Conclusions

Acknowledgements

References

(6K)
FIGURE 1. Calculated (MgCl₂ + CaCl₂) phase diagram, temperature versus mole fraction of CaCl₂.

(7K)
FIGURE 2. Calculated (MgCl₂ + MnCl₂) phase diagram, temperature versus mole fraction of MnCl₂. •, Sandonnini [18] (liquidus); Δ, Il'ichev and Vladimirova [19] (liquidus); , Korzhukov et al. [20].

(5K)
FIGURE 3. Calculated enthalpy of mixing of the (MgCl₂ + MnCl₂) liquid versus the mole fraction of MnCl₂ at 810 °C. Experimental data (•) from Papatheodorou and Kleppa [21].

(7K)
FIGURE 4. Calculated (FeCl₂ + MgCl₂) phase diagram, temperature versus mole fraction of MgCl₂. Δ, Il'ichev and Vladimirova [19] (liquidus); •, Ferrari and Carugati [22] (liquidus); , Korzhukov et al. [23].

(6K)
FIGURE 5. Calculated enthalpy of mixing of the (FeCl₂ + MgCl₂) liquid versus the mole fraction of MgCl₂ at 810 °C. Experimental data (•) from Papatheodorou and Kleppa [21].

(6K)
FIGURE 6. Calculated activity of FeCl₂ (relative to liquid standard state) in the (FeCl₂ + MgCl₂) liquid versus the mole fraction of MgCl₂ at 810 °C. Experimental data (•) from Burylev and Gershunina [24]. (Thin line is ideal activity line)

(6K)
FIGURE 7. Calculated (CoCl₂ + MgCl₂) phase diagram, temperature versus mole fraction of MgCl₂. Experimental data (•) from Ferrari and Inganni [10] (liquidus).

(6K)
FIGURE 8. Calculated enthalpy of mixing of the (CoCl₂ + MgCl₂) liquid versus the mole fraction of MgCl₂ at 810 °C. Experimental data (•) from Papatheodorou and Kleppa [21].

(6K)
FIGURE 9. Calculated (CaCl₂ + MnCl₂) phase diagram, temperature versus mole fraction of MnCl₂. •, Ferrari and Inganni [11]; Δ, Il'ichev and Vladimirova [19]; , Sandonnini [25].

(5K)
FIGURE 10. Calculated enthalpy of mixing of the (CaCl₂ + MnCl₂) liquid versus the mole fraction of MnCl₂ at 810 °C. Experimental data (•) from Papatheodorou and Kleppa [21].

(6K)
FIGURE 11. Calculated (FeCl₂ + CaCl₂) phase diagram, temperature versus mole fraction of CaCl₂. Experimental data (•) from Ferrari and Inganni [11].

(6K)
FIGURE 12. Calculated enthalpy of mixing of the (FeCl₂ + CaCl₂) liquid versus the mole fraction of CaCl₂ at 810 °C. Experimental data (•) from Papatheodorou and Kleppa [21].

(6K)
FIGURE 13. Calculated activity of FeCl₂ (relative to liquid standard state) in the (FeCl₂ + CaCl₂) liquid versus the mole fraction of CaCl₂ at 727 °C and 810 °C. •, Burylev and Gershunina [24] (810 °C); , Ernst et al. [26] (727 °C). (Thin line is ideal activity line)

(6K)
FIGURE 14. Calculated (CaCl₂ + CoCl₂) phase diagram, temperature versus mole fraction of CoCl₂. Experimental data (•) from Ferrari and Inganni [11].

(5K)
FIGURE 15. Calculated enthalpy of mixing of the (CaCl₂ + CoCl₂) liquid versus the mole fraction of CoCl₂ at 810 °C. Experimental data (•) from Papatheodorou and Kleppa [21].

(5K)
FIGURE 16. Calculated (FeCl₂ + MnCl₂) phase diagram, temperature versus mole fraction of MnCl₂. Experimental data (•) from Ferrari et al. [12] (liquidus).

(6K)
FIGURE 17. Calculated (CoCl₂ + MnCl₂) phase diagram, temperature versus mole fraction of MnCl₂. Experimental data (•) from Ferrari and Inganni [10].

(6K)
FIGURE 18. Calculated enthalpy of mixing of the (CoCl₂ + MnCl₂) liquid versus the mole fraction of MnCl₂ at 810 °C. Experimental data (•) from Papatheodorou and Kleppa [21].

(6K)
FIGURE 19. Calculated (FeCl₂ + CoCl₂) phase diagram, temperature versus mole fraction of CoCl₂. Experimental data (•) from Ferrari et al. [12] (liquidus).

(6K)
FIGURE 20. Calculated enthalpy of mixing of the (FeCl₂ + CoCl₂) liquid versus the mole fraction of CoCl₂ at 810 °C. Experimental data (•) from Papatheodorou and Kleppa [21].

(7K)
FIGURE 21. Calculated (CaCl₂ + NiCl₂) phase diagram, temperature versus mole fraction of NiCl₂. Experimental data (•) from Tsemekhman et al. [29].

(8K)
FIGURE 22. Calculated (CoCl₂ + NiCl₂) phase diagram, temperature versus mole fraction of NiCl₂. , Bol'shakov et al. [13]; •, Korzhukov and Khomyakov [14]; Δ, Moskalenko [31].

(7K)
FIGURE 23. Calculated (MnCl₂ + NiCl₂) phase diagram, temperature versus mole fraction of NiCl₂. Experimental data (•) from Korzhukov and Khomyakov [32].

(4K)
FIGURE 24. Calculated enthalpy of mixing for MnCl₂(liquid) + NiCl₂(solid)=(liquid solution) versus the mole fraction of NiCl₂ at 810 °C. Experimental data (•) from Papatheodorou and Kleppa [33].

(8K)
FIGURE 25. Calculated (FeCl₂ + NiCl₂) phase diagram, temperature versus mole fraction of NiCl₂. Experimental data (•) from Korzhukov and Khomyakov [34].

(7K)
FIGURE 26. Calculated (MgCl₂ + NiCl₂) phase diagram, temperature versus mole fraction of NiCl₂. Experimental data (•) from Safonov and Mireev [35].

(6K)
FIGURE 27. Calculated section of the (FeCl₂ + MgCl₂ + MnCl₂) phase diagram at constant mass ratio FeCl₂/(FeCl₂ + MnCl₂) of 0.25, temperature versus mass fraction of MgCl₂. Experimental data (•) from Il'ichev and Vladimirova [19] (liquidus).

(6K)
FIGURE 28. Calculated section of the (FeCl₂ + MgCl₂ + MnCl₂) phase diagram at constant mass ratio FeCl₂/(FeCl₂ + MnCl₂) of 0.50, temperature versus mass fraction of MgCl₂. Experimental data (•) from Il'ichev and Vladimirova [19] (liquidus).

(5K)
FIGURE 29. Calculated section of the (FeCl₂ + MgCl₂ + MnCl₂) phase diagram at constant mass ratio FeCl₂/(FeCl₂ + MnCl₂) of 0.75, temperature versus mass fraction of MgCl₂. Experimental data (•) from Il'ichev and Vladimirova [19] (liquidus).

(7K)
FIGURE 30. Calculated section of the (CaCl₂ + MgCl₂ + MnCl₂) phase diagram at constant MnCl₂ mass fraction of 0.10, temperature versus mass fraction of MgCl₂. Experimental data (•) from Il'ichev and Vladimirova [19].

(7K)
FIGURE 31. Calculated section of the (CaCl₂ + MgCl₂ + MnCl₂) phase diagram at constant MnCl₂ mass fraction of 0.20, temperature versus mass fraction of MgCl₂. Experimental data (•) from Il'ichev and Vladimirova [19].

(7K)
FIGURE 32. Calculated section of the (CaCl₂ + MgCl₂ + MnCl₂) phase diagram at constant MnCl₂ mass fraction of 0.30, temperature versus mass fraction of MgCl₂. Experimental data (•) from Il'ichev and Vladimirova [19].

(7K)
FIGURE 33. Calculated section of the (CaCl₂ + MgCl₂ + MnCl₂) phase diagram at constant MnCl₂ mass fraction of 0.40, temperature versus mass fraction of MgCl₂. Experimental data (•) from Il'ichev and Vladimirova [19].

(6K)
FIGURE 34. Calculated section of the (CaCl₂ + MgCl₂ + MnCl₂) phase diagram at constant MnCl₂ mass fraction of 0.50, temperature versus mass fraction of MgCl₂. Experimental data (•) from Il'ichev and Vladimirova [19].

(7K)
FIGURE 35. Calculated section of the (CaCl₂ + MgCl₂ + MnCl₂) phase diagram at constant mass ratio MgCl₂/(MgCl₂ + CaCl₂) of 0.33, temperature versus mass fraction of MnCl₂. Experimental data (•) from Il'ichev and Vladimirova [19].

(7K)
FIGURE 36. Calculated section of the (CaCl₂ + MgCl₂ + MnCl₂) phase diagram at constant mass ratio MgCl₂/(MgCl₂ + CaCl₂) of 0.50, temperature versus mass fraction of MnCl₂. Experimental data (•) from Il'ichev and Vladimirova [19].

(7K)
FIGURE 37. Calculated section of the (CaCl₂ + MgCl₂ + MnCl₂) phase diagram at constant mass ratio MgCl₂/(MgCl₂ + CaCl₂) of 0.67, temperature versus mass fraction of MnCl₂. Experimental data (•) from Il'ichev and Vladimirova [19].

(11K)
FIGURE 38. Calculated liquidus projection of the (CaCl₂ + MgCl₂ + MnCl₂) system.

(8K)
FIGURE 39. Predicted liquidus projection of the (FeCl₂ + MnCl₂ + CoCl₂) system.

(10K)
FIGURE 40. Predicted liquidus projection of the (FeCl₂ + CoCl₂ + NiCl₂) system.

(10K)
FIGURE 41. Predicted liquidus projection of the (MnCl₂ + CoCl₂ + NiCl₂) system.

(10K)
FIGURE 42. Predicted liquidus projection of the (FeCl₂ + MnCl₂ + NiCl₂) system.

(9K)
FIGURE 43. Calculated phase diagram for a solid alloy consisting of mass fractions of 0.80 Fe, 0.10 Ni, 0.05 Mn and 0.05 Co, exposed to chlorine.

TABLE 1. Thermodynamic properties of compounds

TABLE 2. Ionic radii (in nm) [16] of cations for a coordination number of 6 (octahedral geometry)

References

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2. A.D. Pelton and P. Chartrand. Metall. Mater. Trans. 32A (2001), pp. 1355–1360.

3. P. Chartrand and A.D. Pelton. Can. Metall. Quart. 39 4 (2000), pp. 405–420.

4. P. Chartrand and A.D. Pelton. Metall. Mater. Trans. 32A (2001), pp. 1361–1383.

5. P. Chartrand and A.D. Pelton. Can. Metall. Quart. 40 1 (2001), pp. 13–32.

6. H. Flood and J. Urnes. Z. Elektrochem. 59 (1955), p. 834.

7. A.D. Pelton and W.T. Thompson. Can. J. Chem. 48 10 (1970), pp. 1585–1597.

8. M.W. Chase, Jr., C.A. Davies, J.R. Downey, Jr., D.J. Frurip, R.A. McDonald, A.N. Syverud, in: JANAF Thermochemical Tables, 3rd ed., J. Phys. Chem. Ref. Data 14 (1) 1985

9. I. Barin, Thermochemical Data of Pure Substances. , VCH, Weinheim, Basel (Switzerland), Cambridge, New York (1989).

10. A. Ferrari and A. Inganni. Atti della Reale Accad. dei Lincei 6 8 (1928), p. 238.

11. A. Ferrari and A. Inganni. Atti della Reale Accad. dei Lincei 6 10 (1929), p. 253.

12. A. Ferrari, A. Celeri and F. Giorgi. Atti della Reale Accad. dei Lincei 6 9 (1929), p. 782.

13. K.A. Bol'shakov, P.I. Fedorov and G.D. Agashkina. Russ. J. Inorg. Chem. 3 8 (1958), pp. 235–241.

14. N.G. Korzhukov and K.G. Khomyakov. Vestn. Mosk. Univ., Ser. II 21 5 (1966), pp. 53–56.

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16. R.D. Shannon. Acta Crystallogr. 32A (1976), pp. 751–767.

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18. C. Sandonnini. Atti della Reale Accad. dei Lincei 5 21 (1912), p. 634.

19. V.A. Il'ichev and A.M. Vladimirova. Titan i Ego Splavy, Akad. Nauk SSSR, Inst. Met. 5 (1961), pp. 148–166.

20. N.G. Korzhukov, M.I. Ozerova, K.G. Khomyakov and L.D. Onikienko. Vestn. Mosk. Univ. 4 (1965), pp. 59–60.

21. G.N. Papatheodorou and O.J. Kleppa. J. Chem. Phys. 51 10 (1969), pp. 4624–4632.

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23. N.G. Korzhukov, M.I. Ozerova, K.G. Khomyakov and L.D. Onikienko. Russ. J. Inorg. Chem. 11 1 (1966), pp. 110–111.

24. B.P. Burylev and V.Ya. Gershunina. Fiz. Khim. Elektrokhim. Rasplavl. Tverd. Elektrolitov 1 (1979), pp. 108–110.

25. C. Sandonnini. Atti della Reale Accad. dei Lincei 5 20 (1911), p. 496.

26. W. Ernst, H. Flood and T. Nervik. Z. Anorg. Allg. Chem. 363 (1968), pp. 89–104.

27. I. Barin, O. Knacke and O. Kubaschewski, Thermochemical Properties of Inorganic Substances (Supplement). , Springer-Verlag, Berlin (1977).

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29. L.Sh. Tsemekhman, M.A. Nemoitin and S.E. Vaisburd. J. Appl. Chem. USSR 42 6 (1969), pp. 1321–1322.

30. H. Schaefer. Z. Anorg. Allg. Chem. 278 (1955), p. 300.

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33. G.N. Papatheodorou and O.J. Kleppa. J. Inorg. Nucl. Chem. 32 (1970), pp. 889–900.

34. N.G. Korzhukov and K.G. Khomyakov. Vestn. Mosk. Univ., Ser. Khim. 4 (1966), pp. 68–71.

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36. A.D. Pelton, C.W. Bale, W.T. Thompson: F*A*C*T (Facility for the Analysis of Chemical Thermodynamics), Ecole Polytechnique, Montreal, 2004. Available from

Corresponding author. Tel.: +1-514-340-4711x4304; fax: +1-514-340-5840

Abstract

A complete critical evaluation of all available phase diagram and thermodynamic data has been performed for all condensed phases of the (NaCl + KCl + MgCl₂ + CaCl₂ + MnCl₂ + FeCl₂ + CoCl₂ + NiCl₂) system, and optimized model parameters have been found. The (MgCl₂ + CaCl₂ + MnCl₂ + FeCl₂ + CoCl₂ + NiCl₂) subsystem has been critically evaluated in a previous article. The model parameters obtained for the binary subsystems can be used to predict thermodynamic properties and phase equilibria for the multicomponent system. The Modified Quasichemical Model was used for the molten salt phase, and the (MgCl₂ + MnCl₂ + FeCl₂ + CoCl₂ + NiCl₂) solid solution was modeled using a cationic substitutional model with an ideal entropy and an excess Gibbs free energy expressed as a polynomial in the component mole fractions. Finally, the (Na,K)(Mg,Ca,Mn,Fe,Co,Ni)Cl₃ and the (Na,K)₂(Mg,Mn,Fe,Co,Ni)Cl₄ solid solutions were modeled using the Compound Energy Formalism.

Author Keywords: Molten chlorides; Transition metal chlorides; Hot corrosion; Thermodynamic modeling; Thermodynamic database

Article Outline

1. Introduction

2. Thermodynamic data for the pure compounds

3. Thermodynamic model for the liquid phase

4. Thermodynamic model for the solid solutions

5. Binary mixtures of divalent metal chlorides with NaCl

5.1. The (NaCl + MnCl₂) system

5.2. The (NaCl + FeCl₂) system

5.3. The (NaCl + CoCl₂) system

5.4. The (NaCl + NiCl₂) system

6. Binary mixtures of divalent metal chlorides with KCl

6.1. The (KCl + MnCl₂) system

6.2. The (KCl + FeCl₂) system

6.3. The (KCl + CoCl₂) system

6.4. The (KCl + NiCl₂) system

7. Ternary systems (NaCl + KCl + MCl₂) with M=Mg, Ca, Mn, Fe, Co and Ni

7.1. The (NaCl + KCl + MnCl₂) system

7.2. The (NaCl + KCl + FeCl₂) system

7.3. The (NaCl + KCl + CoCl₂) system

7.4. The (NaCl + KCl + NiCl₂) system

8. Other ternary and quaternary systems

8.1. The (NaCl + MgCl₂ + FeCl₂) system

8.2. The (NaCl + CaCl₂ + FeCl₂) system

8.3. The (KCl + CaCl₂ + FeCl₂) system

8.4. The (NaCl + CoCl₂ + NiCl₂) system

8.5. The (KCl + CoCl₂ + NiCl₂) system

8.6. The (KCl + MgCl₂ + NiCl₂) and (NaCl + KCl + MgCl₂ + NiCl₂) systems

8.7. The (NaCl + MgCl₂ + CaCl₂ + MnCl₂) system

9. Multicomponent system (NaCl + KCl + MgCl₂ + CaCl₂ + MnCl₂ + FeCl₂ + CoCl₂ + NiCl₂)

10. Conclusions

Acknowledgements

References

(8K)
FIGURE 1. Calculated enthalpy of mixing of the (KCl + MCl₂) binary liquids (M=Mg, Ca, Mn, Fe, Co, Ni) versus the mole fraction of MCl₂. Østvold [7]: •, CaCl₂ (810 °C). Kleppa and McCarty [8]: o, MgCl₂ (800 °C). Papatheodorou and Kleppa [9]: , MnCl₂ (810 °C); , FeCl₂ (810 °C); , CoCl₂ (810 °C). Dotted curve: NiCl₂ (810 °C).

(10K)
FIGURE 2. Calculated entropy of mixing of the (KCl + MCl₂) binary liquids (M=Mg, Ca, Mn, Fe, Co, Ni) versus the mole fraction of MCl₂.

(9K)
FIGURE 3. Calculated enthalpy of mixing of the (NaCl + MCl₂) binary liquids (M=Mg, Ca, Mn, Fe, Co, Ni) versus the mole fraction of MCl₂ at 810 °C. Østvold [7]: •, CaCl₂. Kleppa and McCarty [8]: o, MgCl₂. Papatheodorou and Kleppa [9]: , MnCl₂; , FeCl₂; , CoCl₂. Dotted curve: NiCl₂.

(9K)
FIGURE 4. Calculated entropy of mixing of the (NaCl + MCl₂) binary liquids (M=Mg, Ca, Mn, Fe, Co, Ni) versus the mole fraction of MCl₂ at 810 °C.

(10K)
FIGURE 5. Calculated (NaCl + MnCl₂) phase diagram, temperature versus mole fraction of MnCl₂. o, Sandonnini and Scarpa [16]; , Safonov et al. [17]; +, Yakovleva et al. [18]; , Seifert and Koknat [19]; , Seifert and Flohr [20].

(6K)
FIGURE 6. Calculated activity of NaCl (relative to liquid standard state) in the (NaCl + MnCl₂) liquid versus the mole fraction of MnCl₂ at 612 °C and 812 °C. Experimental data from Østvold [25]: , 612 °C; •, 812 °C.

(8K)
FIGURE 7. Calculated (NaCl + FeCl₂) phase diagram, temperature versus mole fraction of FeCl₂. o, Ionov et al. [26]; , Galitskii et al. [27].

(5K)
FIGURE 8. Calculated activity coefficient of FeCl₂ (relative to liquid standard state) in the (NaCl + FeCl₂) liquid versus the mole fraction of FeCl₂ at 820 °C and 920 °C. Experimental data from Kuhnl and Besenbruch [29]: o, 820 °C; •, 920 °C.

(8K)
FIGURE 9. Calculated (NaCl + CoCl₂) phase diagram, temperature versus mole fraction of CoCl₂. o, Bol'shakov et al. [30]; •, Seifert and Thiel [31] (smoothed data).

(7K)
FIGURE 10. Calculated activity of NaCl (relative to liquid standard state) in the (NaCl + CoCl₂) liquid versus the mole fraction of CoCl₂ between 610 °C and 816 °C. Experimental data from Dutt and Østvold [32]: , 610 °C; , 710 °C; , 725 °C; o, 816 °C.

(6K)
FIGURE 11. Calculated Henrian activity coefficient of CoCl₂ (relative to liquid standard state) in the (NaCl + CoCl₂) (869 °C), (KCl + CoCl₂) (861 °C) and ([NaCl + KCl(1:1)] + CoCl₂) (759 °C) liquids versus the mole fraction of CoCl₂. Experimental data from Tumidajski and Flengas [33]: •, (NaCl + CoCl₂) (869 °C); o, (KCl + CoCl₂) (861 °C); , ([NaCl + KCl(1:1)] + CoCl₂) (759 °C).

(7K)
FIGURE 12. Calculated (NaCl + NiCl₂) phase diagram, temperature versus mole fraction of NiCl₂. , Bol'shakov et al. [30]; •, Fedoseev [34].

(6K)
FIGURE 13. Calculated enthalpy of mixing for ACl(liquid) + NiCl₂(solid)=(liquid solution) versus the mole fraction of NiCl₂ at 810 °C (A=Na, K). Experimental data from Papatheodorou and Kleppa [36]: •, (NaCl + NiCl₂); o, (KCl + NiCl₂).

(5K)
FIGURE 14. Calculated activity coefficient of NiCl₂ (relative to solid standard state) in the (NaCl + NiCl₂) liquid versus the mole fraction of NiCl₂ at 800 °C and 900 °C. Tumidajski and Flengas [33]: , 884 °C. Hamby and Scott [37]: •, 800 °C; , 900 °C.

(5K)
FIGURE 15. Calculated emf of the cell Ni(s)/(NaCl + NiCl₂) (x[NiCl₂]=0.1589)/-alumina/(NaCl + NiCl₂)(l)/Ni(s) versus the mole fraction of NiCl₂. Experimental data from Roumieu and Pelton [38]: o, 800 °C; , 900 °C; , 1000 °C.

(9K)
FIGURE 16. Calculated (KCl + MnCl₂) phase diagram, temperature versus mole fraction of MnCl₂ (the transition at 386 °C is not calculated). o, Sandonnini and Scarpa [16]; , Safonov et al. [17]; +, Yakovleva et al. [18]; , Seifert and Koknat [19]; , Natsvlishvili and Bergman [41].

(6K)
FIGURE 17. Calculated activity of KCl (relative to liquid standard state) in the (KCl + MnCl₂) liquid versus the mole fraction of MnCl₂ between 690 °C and 790 °C. Experimental data from Østvold [25]: , 690 °C; , 710 °C; •, 790 °C.

(10K)
FIGURE 18. Calculated (KCl + FeCl₂) phase diagram, temperature versus mole fraction of FeCl₂ (the transitions at 266 °C and 303 °C are not calculated). o, Ionov et al. [26]; , Galitskii et al. [27]; , Pinch and Hirshon [44].

(7K)
FIGURE 19. Calculated activity coefficient of FeCl₂ (relative to liquid standard state) in the (KCl + FeCl₂) liquid versus the mole fraction of FeCl₂ between 727 °C and 920 °C. Kuhnl and Besenbruch [29]: , 820 °C; , 920 °C. Ernst et al. [45]: +, 727 °C; , 777 °C. Josiak [46]: o, 700 °C.

(7K)
FIGURE 20. Calculated (KCl + CoCl₂) phase diagram, temperature versus mole fraction of CoCl₂ (the transition at 124 °C is not calculated). Experimental data (•) from Seifert [47].

(6K)
FIGURE 21. Calculated activity of KCl (relative to liquid standard state) in the (KCl + CoCl₂) liquid versus the mole fraction of CoCl₂ at 717 °C and 790 °C. Experimental data from Dutt and Østvold [32]: , 709 °C; , 717 °C; •, 790 °C.

(8K)
FIGURE 22. Calculated (KCl + NiCl₂) phase diagram, temperature versus mole fraction of NiCl₂ (the transitions at 287 °C and 480 °C are not calculated). •, Seifert and Thiel [31]; , Belyaev et al. [50]; , Bazhenov et al. [51] (smoothed data).

(5K)
FIGURE 23. Calculated activity coefficient of NiCl₂ (relative to solid standard state) in the (KCl + NiCl₂) liquid versus the mole fraction of NiCl₂ between 800 °C and 900 °C. Tumidajski and Flengas [33]: , 820 °C. Hamby and Scott [37]: •, 800 °C; , 900 °C.

(11K)
FIGURE 24. Calculated liquidus projection of the (NaCl + KCl + MnCl₂) system.

(9K)
FIGURE 25. Calculated section of the (NaCl + KCl + MnCl₂) phase diagram at constant molar ratio KCl/(KCl + MnCl₂) of 0.35, temperature versus mole fraction of NaCl. Notations: A, MnCl₂; B, Na₆MnCl₈; C, Na₂MnCl₄; D, Na₉Mn₁₁Cl₃₁; E, Na₂Mn₃Cl₈; F, KMnCl₃. Experimental data (•) from Safonov et al. [17].

(8K)
FIGURE 26. Calculated (KMnCl₃ + NaCl) section of the (NaCl + KCl + MnCl₂) phase diagram, temperature versus mole fraction of NaCl. Experimental data (•) from Safonov et al. [17].

(10K)
FIGURE 27. Calculated section of the (NaCl + KCl + MnCl₂) phase diagram at constant molar ratio KCl/(KCl + MnCl₂) of 0.65, temperature versus mole fraction of NaCl. Notations: F, KMnCl₃; G, K₃Mn₂Cl₇; H, K₄MnCl₆. Experimental data (•) from Safonov et al. [17].

(9K)
FIGURE 28. Calculated section of the (NaCl + KCl + MnCl₂) phase diagram at constant 50 mol% KCl, temperature versus mole fraction of NaCl. Notations: F, KMnCl₃; G, K₃Mn₂Cl₇; H, K₄MnCl₆. Experimental data (•) from Safonov et al. [17].

(7K)
FIGURE 29. Calculated section of the (NaCl + KCl + MnCl₂) phase diagram at constant 50 mol% MnCl₂, temperature versus mole fraction of NaCl. Notations: C, Na₂MnCl₄; D, Na₉Mn₁₁Cl₃₁; E, Na₂Mn₃Cl₈; F, KMnCl₃. Experimental data (•) from Safonov et al. [17].

(10K)
FIGURE 30. Calculated liquidus projection of the (NaCl + KCl + FeCl₂) system (the very small field of crystallization of Na₂FeCl₄ is not visible on the scale of the diagram).

(7K)
FIGURE 31. Calculated liquidus temperatures of (NaCl + KCl + FeCl₂) mixtures versus the molar ratio x_KCl/(x_NaCl + x_KCl) at constant mole fractions of FeCl₂ of 0.1, 0.2, 0.3, 0.4 and 0.6. Experimental data from Tronina et al. [55]: o, 0.1; •, 0.2; , 0.3; , 0.4; , 0.6.

(8K)
FIGURE 32. Calculated (NaCl + KFeCl₃) section of the (NaCl + KCl + FeCl₂) phase diagram, temperature versus mole fraction of KFeCl₃. Experimental data (•) from Tronina et al. [55].

(6K)
FIGURE 33. Calculated activity coefficient of FeCl₂ (relative to liquid standard state) in the (NaCl + KCl + FeCl₂) liquid versus the mole fraction of FeCl₂ at constant molar ratio NaCl/(NaCl + KCl) of 0.232 and 0.768, at 820 °C and 920 °C. Experimental data from Kuhnl and Besenbruch [29]: , 0.232 (820 °C); •, 0.768 (820 °C); , 0.232 (920 °C); o, 0.768 (920 °C).

(5K)
FIGURE 34. Calculated activity coefficient of NiCl₂ (relative to solid standard state) in the (NaCl + KCl + NiCl₂) liquid versus the mole fraction of NiCl₂ at constant molar ratio NaCl/(NaCl + KCl) of 0.5, at 700 °C and 800 °C. Tumidajski and Flengas [33]: , 762 °C. Hamby and Scott [37]: •, 700 °C; , 800 °C.

(5K)
FIGURE 35. Calculated activity coefficient of FeCl₂ (relative to liquid standard state) in the (NaCl + MgCl₂ + FeCl₂) liquid versus the mole fraction of FeCl₂ at constant molar ratio NaCl/(NaCl + MgCl₂) of 0.5, at 820 °C and 920 °C. Experimental data from Kuhnl and Besenbruch [29]: o, 820 °C; , 920 °C.

(8K)
FIGURE 36. Calculated activity coefficient of FeCl₂ (relative to liquid standard state) in the (KCl + CaCl₂ + FeCl₂) liquid versus the mole fraction of FeCl₂ at constant molar ratio CaCl₂/(KCl + CaCl₂) of 0.2 and 0.5. Ernst et al. [45]: •, 0.2 (627 °C); , 0.2 (727 °C); , 0.2 (777 °C); +, 0.5 (627 °C); , 0.5 (727 °C); , 0.5 (777 °C). Kuhnl et al. [56]: , 0.5 (820 °C); , 0.5 (920 °C).

(9K)
FIGURE 37. Calculated liquidus projection of the (NaCl + CoCl₂ + NiCl₂) system.

(8K)
FIGURE 38. Calculated section of the (NaCl + CoCl₂ + NiCl₂) phase diagram at constant NaCl mass fraction of 0.24, temperature versus mass fraction of NiCl₂. Experimental data (•) from Bol'shakov et al. [57].

(9K)
FIGURE 39. Calculated section of the (NaCl + CoCl₂ + NiCl₂) phase diagram at constant NaCl mass fraction of 0.35, temperature versus mass fraction of NiCl₂. Experimental data (•) from Bol'shakov et al. [57].

(7K)
FIGURE 40. Calculated section of the (NaCl + CoCl₂ + NiCl₂) phase diagram at constant NaCl mass fraction of 0.73, temperature versus mass fraction of NiCl₂. Experimental data (•) from Bol'shakov et al. [57].

(10K)
FIGURE 41. Calculated section of the (NaCl + CoCl₂ + NiCl₂) phase diagram at constant mass ratio NiCl₂/(CoCl₂ + NiCl₂) of 0.25, temperature versus mass fraction of NaCl. Experimental data (•) from Bol'shakov et al. [57].

(9K)
FIGURE 42. Calculated section of the (NaCl + CoCl₂ + NiCl₂) phase diagram at constant mass ratio NiCl₂/(CoCl₂ + NiCl₂) of 0.50, temperature versus mass fraction of NaCl. Experimental data (•) from Bol'shakov et al. [57].

(9K)
FIGURE 43. Calculated section of the (NaCl + CoCl₂ + NiCl₂) phase diagram at constant mass ratio NiCl₂/(CoCl₂ + NiCl₂) of 0.75, temperature versus mass fraction of NaCl. Experimental data (•) from Bol'shakov et al. [57].

(6K)
FIGURE 44. Calculated activity coefficient of NiCl₂ (relative to solid standard state) in the (KCl + CoCl₂ + NiCl₂) liquid versus the molar ratio x(NiCl₂)/[x(CoCl₂) + x(NiCl₂)] at constant mole fractions of KCl of 0.5, 0.75 and 0.9. Experimental data from Tumidajski and Pickles [58]: , 0.5 (692 °C); , 0.75 (647 °C); •, 0.9 (797 °C).

(5K)
FIGURE 45. Calculated activity coefficient of NiCl₂ (relative to solid standard state) versus the mole fraction of NiCl₂ at 475 °C in ternary (KCl + MgCl₂ + NiCl₂) melts at constant molar ratio KCl/MgCl₂=67.5/32.5, and in quaternary (NaCl + KCl + MgCl₂ + NiCl₂) melts at constant molar ratio NaCl/KCl/MgCl₂=30/20/50. Experimental data from Jindal [59]: •, KCl/MgCl₂=67.5/32.5; o, NaCl/KCl/MgCl₂=30/20/50.

(8K)
FIGURE 46. Calculated section of the (NaCl + MgCl₂ + CaCl₂ + MnCl₂) phase diagram at constant mass ratio MgCl₂/CaCl₂/MnCl₂=60/30/10, temperature versus mass fraction of NaCl. Notations: A, (MgCl₂ + MnCl₂)(ss); B, (CaCl₂ + MgCl₂)(ss); C, (NaCl + CaCl₂)(ss); D, Na(Mg,Ca,Mn)Cl₃(ss); E, Na₂(Mg,Mn)Cl₄(ss). Experimental data (•) from Il'ichev and Vladimirova [60].

(8K)
FIGURE 47. Calculated section of the (NaCl + MgCl₂ + CaCl₂ + MnCl₂) phase diagram at constant mass ratio MgCl₂/CaCl₂/MnCl₂=1/1/1, temperature versus mass fraction of NaCl. Notations: A, (MgCl₂ + MnCl₂)(ss); B, (CaCl₂ + MgCl₂)(ss); C, (NaCl + CaCl₂)(ss); D, Na(Mg,Ca,Mn)Cl₃(ss); E, Na₂(Mg,Mn)Cl₄(ss). Experimental data (•) from Il'ichev and Vladimirova [60].