Thermodynamics of Mixtures Containing Organic Carbonates. 14

Aug 23, 2003 - Excess Molar Gibbs Energies for 1-Hexanol + Dimethyl or Diethyl Carbonate Systems at 353.15 and 363.15 K. Comparison with ERAS Results...
0 downloads 0 Views 109KB Size
4382

Ind. Eng. Chem. Res. 2003, 42, 4382-4388

GENERAL RESEARCH Thermodynamics of Mixtures Containing Organic Carbonates. 14. Excess Molar Gibbs Energies for 1-Hexanol + Dimethyl or Diethyl Carbonate Systems at 353.15 and 363.15 K. Comparison with ERAS Results Andrzej Sporzynski,† Monika Szurgocinska,† Urszula Domanska,† and Juan Antonio Gonza´ lez*,‡ Physical Chemistry Division, Faculty of Chemistry, Warsaw University of Technology, 00-664 Warsaw, Poland, and GETEF, Departamento de Termodina´ mica y Fı´sica Aplicada, Facultad de Ciencias, Universidad de Valladolid, 47071 Valladolid, Spain

Vapor-liquid equilibria (P-x measurements) at 353.15 and 363.15 K for 1-hexanol + dimethyl carbonate or + diethyl carbonate are determined by an ebullometric method. The data are reduced using Barker’s method. All of the systems present positive deviations from Raoult’s law. Mixtures are studied in the framework of the ERAS model assuming that 1-alkanols are the only self-associated compounds in the investigated solutions. According to the high HE (excess molar enthalpy) values of 1-alkanol + linear organic carbonate systems, the model predicts a weak cross association between the mixture components. The deviations between the experimental GE (excess molar Gibbs energy) and HE values and the ERAS results can be ascribed to the existence of strong polar interactions between carbonate molecules, not described properly by the model. 1. Introduction Organic carbonates, linear or cyclic, are widely employed in industry. They are used in the synthesis of organic compounds,1 e.g., pharmaceuticals2 and agricultural chemicals, and as solvents for many synthetic and natural resins.3 They are also important in the Li battery technology.4 Dimethyl carbonate (DMC) is used in the replacement of hazardous chemicals,5,6 as a fuel additive,7 or in the design of new refrigerants.8 In the framework of the TOM Project (Thermodynamics of Organic Mixtures),9,10 the OCO program is developed to get a better understanding of the interactions between the O (oxygen) and CO (carbonyl) groups in the same or in different molecules. Particularly, we are engaged in a systematic study of mixtures involving organic carbonates (the OCOO group). Up to now, we have reported data on vapor-liquid equilibria (VLE),11-14 liquid-liquid equilibria,15,16 HE,17,18 excess molar volumes,19,20 and solid-liquid equilibria16,21,22 of systems formed by DMC and diethyl carbonate (DEC) and alkane, benzene, toluene, CCl4, or 1-alkanol. We have also presented the characterization of the OCOO/ aliphatic, OCOO/cyclic, OCOO/aromatic, OCOO/CCl4,23-25 and OCOO/OH22 contacts in terms of DISQUAC, a purely physical model.9,10 1-Alkanol + linear organic carbonate systems have been also studied22 using the ERAS model.26 Then, we showed that, in these solutions, * To whom correspondence should be addressed. † Warsaw University of Technology. ‡ Universidad de Valladolid.

the strong polar interactions between carbonate molecules are more important than the self-association of the alkanol or than the association between the alcohol and the carbonate. For this reason, ERAS predictions for HE are improved by DISQUAC. The purpose of this paper is to investigate the ability of ERAS to describe GE for 1-alkanol + linear organic carbonate mixtures. For a more complete study, we also report VLE (P-x) measurements and the corresponding GE for 1-hexanol + DMC or + DEC at 353.15 and 363.15 K. 2. Experimental Section 2.1. Materials. The origins of the chemicals (in parentheses are Chemical Abstracts registry numbers) are as follows: 1-hexanol (anhydrous; 111-27-3, Aldrich); DMC (616-38-6) and DEC (105-58-8) (anhydrous, mole fraction > 99%) were supplied by Aldrich and stored over freshly activated molecular sieves of type 4 A (Union Carbide). All compounds were checked by gas-liquid chromatography analysis, and no significant impurities were found. The purity of 1-hexanol was determined to be 99.9%. 2.2. Apparatus and Procedure. The VLE was determined by an ebulliometric method, which reports, at constant temperature, T, pressure (P) values as a function of the liquid-phase mole fraction. The ebulliometer was designed by Rogalski and Malanoswki27 and was used with some modification of taking samples to enable the sampling of the liquid to be made without disturbing the working conditions.28 Pressure stability was obtained using a buffer vessel (50 dm3). Pressure

10.1021/ie0303000 CCC: $25.00 © 2003 American Chemical Society Published on Web 08/23/2003

Ind. Eng. Chem. Res., Vol. 42, No. 19, 2003 4383 Table 1. VLE for the 1-Hexanol (1) + DMC (2) System at Temperature T x1

P/kPa

y1,cal

0.0212 0.0771 0.2296 0.3525 0.4484

70.51 67.41 60.25 55.11 51.14

T ) 353.15 Ka 0.003 0.5388 0.011 0.6592 0.029 0.7852 0.041 0.8808 0.051 0.9235

x1

0.0193 0.0771 0.2253 0.3538 0.4386

98.09 93.62 83.70 75.67 70.79

T ) 363.15 Kb 0.003 0.5388 0.013 0.6553 0.033 0.7844 0.049 0.8622 0.059

P/kPa

y1,cal

46.90 40.19 31.54 23.12 17.24

0.061 0.078 0.109 0.165 0.224

63.59 55.32 42.14 31.89

0.073 0.094 0.138 0.195

The parameters of eq 1 are A1 ) 1.009; A2 ) 0.032; A3 ) 0.0727; σr(P) (eq 3) ) 0.008. b The parameters of eq 1 are A1 ) 0.872; A2 ) -0.0202; A3 ) -0.0275; σr(P) (eq 3) ) 0.004.

Table 3. Total Pressures, Pi°, Molar Volumes, VLi , and Virial Coefficients, Bii, of Pure Compounds at Temperature T compound

T/K

Pi°/kPa

1-hexanol

353.15 363.15 353.15

4.13b 7.0b 72.35c 74.75d 72.36e 100.5c 100.7e 21.26c 21.26d 21.4e 31.14c 31.21e

DMC

363.15 DEC

363.15

a

Table 2. VLE for the 1-Hexanol (1) + DEC (2) System at Temperature T x1

P/kPa

y1,cal

0.0064 0.0276 0.0770 0.1361 0.1854 0.2919

21.04 20.69 20.36 19.20 18.60 17.22

T ) 353.15 Ka 0.002 0.4274 0.009 0.4588 0.025 0.5091 0.046 0.6540 0.062 0.6951 0.098 0.7772

x1

0.0083 0.0315 0.0751 0.1341 0.1893 0.2917 0.4284

30.87 30.39 29.29 28.15 27.21 25.51 23.18

T ) 363.15 Kb 0.002 0.4971 0.010 0.5163 0.027 0.6447 0.051 0.6910 0.070 0.7608 0.111 0.8861 0.156

P/kPa

y1,cal

15.86 14.98 14.67 12.56 11.76 10.23

0.142 0.152 0.169 0.231 0.256 0.323

22.01 21.64 18.69 17.30 15.59 11.50

0.182 0.189 0.259 0.294 0.359 0.546

a The parameters of eq 1 are A ) 0.599; A ) 0.0195; A ) 1 2 3 -0.1254; σr(P) (eq 3) ) 0.008. b The parameters of eq 1 are A1 ) 0.529; A2 ) -0.0382; A3 ) -0.0894; A4 ) 0.2327; σr(P) (eq 3) ) 0.004.

measurements were made with a mercury manometer equipped with a cathetometer with a resolution of (0.01 mm, which gives an accuracy of the vapor-pressure measurements to be better than (0.03 kPa. Vaporpressure measurements were corrected according to the standard method.29 The temperature was measured using a calibrated platinum resistance thermometer (1220 by Frontec Pajala AB, Sweden), with an accuracy of (0.01 K. All of the measurements were conducted in a purified argon atmosphere. The composition of the liquid was determined by a precision refractometer (Carl Zeiss, Jena), with an accuracy of (0.000 01 at 298.15 ( 0.01 K. A calibration curve was made for each mixture, and the accuracy of the composition determination was better than (0.0005 in mole fraction. 2.3. Results and Data Reduction. The experimental P-x1 data at 353.15 and 363.15 K are listed in Tables 1 and 2. No data have been found in the literature for comparison. The P-x1 measurements were reduced using Barker’s method30 to obtain values of y1 (mole fraction in the vapor phase) and γi, the activity coefficient of component i in the liquid state. To this end, it was assumed that GE is represented by an equation of the Redlich-Kister type: k

GE/RT ) x1(1 - x1)

∑ Am(2x1 - 1)m m)0

(1)

353.15

VLi / mol-1)

(cm3

Biia/ (cm3 mol-1) -2730 -2335 -989

133.15b 134.75b 88d 90f

-923

133d

-1702

135f

-1573

a B /(cm3 mol-1) ) -1195 (T ) 353.15 K); -1112 (T ) 363.15 12 K) for 1-hexanol + DMC; B12/(cm3 mol-1) ) -1564 (T ) 353.15 K); -1448 (T ) 363.15 K) for 1-hexanol + DEC. b Reference 41. c This work. d Reference 42; e Reference 43. f Extrapolated using data from ref 42.

Table 4. Boiling Temperatures, Tb, at 101.325 kPa, Critical Temperatures, Tc, Pressures, Pc, Mean Radii of Gyration, RD, and Dipole Moments, µ, in the Vapor Phase of 1-Hexanol and Linear Organic Carbonates compound

Tb/K

Tc/K

Pc/K

RD/A

µ/D

1-hexanol DMC DEC

430.2a 363.6b 400a

610a 547c 577c

34.6a 43.4c 34.2c

3.87d 2.98d 3.78d

1.55a 0.87e 0.90a

a Reference 44. b Reference 45. c Calculated using Joback’s method.45 d Calculated from parachor values.45 e Reference 46.

The parameters in eq 1 were determined by minimizing the sum of squares between the measured and calculated pressures, with all of the points equally weighted. Calculated pressures are obtained from

Pcalc )

[

x1γ1P1° exp

]

-(B11 - VL1 )(P - P1°) - Pδ12y22 + RT

[

x2γ2P2° exp

]

-(B22 - VL2 )(P - P2°) - Pδ12y12 (2) RT

where Pi° is the vapor pressure and VLi the saturated liquid volume of the pure component i at temperature T. The second virial coefficients are denoted by Bij, and δ12 ) 2B12 - B11 - B12. Equation 2 is valid assuming that the vapor phase of the mixture, as well as the vapor in equilibrium with the pure components, is described by the volume-explicit virial equation terminated after the second virial coefficient; VLi is constant over the pressure range considered, the liquid partial molar volume of each component is invariant with composition, and the standard states for γi are the pure components at the same T and P as those of the mixtures. The values of the second virial coefficients and saturated liquid volumes used in the calculations are given in Table 3. Second virial coefficients were determined from the Hayden-O’Connell method.31 The constants needed for their determination are given in Table 4. For 1-hexanol, the association parameter used was 1.55. The solvation parameters between alcohol and carbonates were neglected. Parameters of eq 1 together with the relative standard deviation in P from the corresponding adjustement,

4384 Ind. Eng. Chem. Res., Vol. 42, No. 19, 2003 Table 5. ERAS Parametersa for Pure Compounds at Temperature T compound

T/K

Vi/(cm3 mol-1)

Vi*/(cm3 mol-1)

Pi*/(J cm-3)

Ki

∆hi*/(kJ mol-1)

∆vi*/(cm3 mol-1)

methanol ethanol 1-propanol 1-pentanol 1-hexanol

313.15 313.15 313.15 298.15 298.15 353.15 363.15 313.15 353.15 363.15 353.15 363.15

41.12 59.66 76.29 108.69 125.19 133.15b 134.75b 86.48 88b 90b 133b 135b

34.23 47.26. 61.49 89.76 103.52 105.68 106.3 65.54 63.5 64.13 97.45 97.81

420.7 392.6 385.63 411.0 431.1 401.1 397.1 693.1 669.3 657.4 565.9 556.3

607 317 121.3 153 120 24.6 19.6 0 0 0 0 0

-25.1 -25.1 -25.1 -25.1 -25.1 -25.1 -25.1 0 0 0 0 0

-5.6 -5.6 -5.6 -5.6 -5.6 -5.6 -5.6 0 0 0 0 0

DMC DEC

a V , molar volume; V *, reduction parameter for volume; P *, reduction parameter for pressure; K , equilibrium constant; ∆h *, association i i i i i enthalpy; ∆vi*, association volume. The reduction parameters were determined from P-V-T data reported in refs 35, 44, and 47-49 and using eqs 8-10. b See Table 3.

defined as

components but also for the mixture:

σr(P) )

{

1 N-k

]}

[



Pcalc - Pexp Pexp

2 1/2

(3)

are given as footnotes in Tables 1 and 2. In eq 3, N is the number of data points and k the number of fitted parameters for each system. All of the solutions show positive deviations from Raoult’s law and do not present azeotropic behavior. 3. ERAS Model This model combines the real association solution model32 with Flory’s equation of state.33 The excess functions are split into two additive terms that arise from hydrogen-bonding effects (the so-called chemical contribution) and nonpolar van der Waals interactions including free-volume effects (the so-called physical interactions). Moreover, it is assumed that only consecutive linear association occurs between A (1-alkanol) molecules, which is described by a chemical equilibrium constant KA independent of the chain length i of the associated species, according to KA

Am + A1 {\} Am+1

(4)

Linear organic carbonates (B) are considered to be not self-associated. The cross association between A and B molecules is represented by KAB

Am + B {\} AmB

(5)

The dependence of Ki on temperature is given by the van’t Hoff relation

[

(

∆hi* 1 1 Ki ) K0 exp R T T0

)]

(6)

where ∆hi* is the enthalpy variation for reactions (4) and (5), which corresponds to the hydrogen bond energy. K0 is the association constant at temperature T0. Reactions (4) and (5) are also characterized by the volume change ∆vi* related to the formation of the linear chains. The physical contribution is derived from Flory’s equation of state,33 which holds not only for pure

P h iV hi T hi

)

V h i1/3 V h i1/3 - 1

-

1 V h iT hi

(7)

with P h i ) P/Pi*, V h i ) Vi/Vi*, and T h i ) T/Ti* being the reduced pressure, volume, and temperature, respectively. Pi*, Vi*, and Ti* are the corresponding reduction parameters. For associating molecules, the procedure to obtain the reduction parameters is somewhat different from the original one applied in Flory’s model. In ERAS, the reduction parameters of the pure compounds are calculated from P-V-T data [density (d), thermal expansion (RP), and isothermal compressibility (κT)], but they also depend on Ki, ∆hi*, and ∆vi*. The method is explained elsewhere.34 The reduction parameters for the binary mixtures are calculated using the mixing rules.34 The XAB parameter, which characterizes the difference of dispersive intermolecular interactions between molecules A and B in the solution and in the pure components, is the only adjustable parameter of the physical part of HE and VE,22. On the other hand, for VLE or liquid-liquid equilibria (LLE) calculations, a new parameter, QAB, is needed in order to characterize the entropic contribution to the difference of intermolecular interactions.35 Expressions for the chemical and physical contributions to HE, VE, or ln γi can be found elsewhere36 and will not be repeated here. To calculate the reduction parameters of pure compounds at T * 298.15 K (Table 5), the following expressions37 were used to determine the values of d (density), Rp, and γ ()Rp/κT):

d ) d0 exp(-Rp∆T)

(8)

Rp ) R0 + R02(7 + 4R0T)∆T/3

(9)

γ ) γ0 - γ0(1 + 2R0T)∆T/T

(10)

The KA, ∆hA*, and ∆vA* parameters are known from HE and VE data at 298.15 K of 1-alkanol + alkane mixtures34 (Table 5). Similarly, KAB, ∆hAB*, and ∆vAB* were determined in a previous work22 (Table 6) on the basis of data for 1-alkanol + linear organic carbonate systems. Here, the QAB values were obtained from GE data, which is the usual procedure,35 and the XAB values were calculated using the available38 HE data at T *

Ind. Eng. Chem. Res., Vol. 42, No. 19, 2003 4385 Table 6. ERAS Parametersa for 1-Alkanol + DMC or + DEC Mixtures system

T/K

KAB

∆hAB*/(kJ mol-1)

∆vAB*/(cm3 mol-1)

XAB/(J cm-3)

QAB/(J cm-3 mol-1)

methanol + DMC ethanol + DMC 1-propanol + DMC 1-hexanol + DMC

313.15 313.15 313.15 353.15 363.15 298.15 298.15 353.15 363.15

18.9 10.4 10.4 9. 8.9 10.5 8 6.2 6.

-3.0 -3.0 -3.0 -3.0 -3.0 -4.0 -4.0 -4.0 -4.0

-7.5 -7.5 -7.5 -7.5 -7.5 -7.5 -7.5 -7.5 -7.5

9 24 28 29 29 17.7 21 21 21

0.015 0. -0.026 -0.07 -0.07

1-pentanol + DEC 1-hexanol + DEC

0.023 0.020

a K , association constant of 1-alkanol with carbonate;22 ∆h *, association enthalpy of 1-alkanol with carbonate;22 ∆v *, association AB AB AB volume of 1-alkanol with carbonate;22 XAB, adjustable physical parameter in the ERAS model (this work); QAB, entropic parameter needed for GE calculations (this work).

Figure 1. GE for 1-alkanol (1) + DMC (2) systems. Points, experimental results: (9) methanol,38 T ) 313.15 K; (b) 1-hexanol (this work), T ) 353.15 K. Solid lines, ERAS calculations using parameters from Tables 5 and 6. Dashed lines, DISQUAC results with interaction parameters from the literature.22

298.15 K. The XAB and QAB parameters are collected in Tables 5 and 6. The total relative molecular volumes and surfaces of the mixture compounds, needed to calculate their surface-to-volume ratios (s), were obtained additively on the basis of Bondi’s method.39 4. Discussion GE values from VLE measurements for 1-hexanol + DMC or + DEC are plotted in Figures 1-3. We note that, at a given temperature, GE (1-hexanol + DMC) > GE (1-hexanol + DEC) (Figure 3); i.e., interactions between like molecules are stronger in systems with DMC. At equimolar composition and 313.15 K, for systems with DMC,38 GE(methanol) ) 939 J mol-1, GE(ethanol) ) 953 J mol-1, and GE(1-propanol) ) 966 J mol-1. These rather constant values may be well attributed to a certain enthalpic-entropic compensation. For example, at the same conditions as above, TSE ()HE - GE) ) 604 J mol-1 for methanol + DMC38 (HE ) 1543 J mol-1) and TSE ) 1355 J mol-1 for 1-propanol + DMC38 (HE ) 2321 J mol-1). These high TSE and HE values together with the symmetrical GE and HE curves (Figures 1-4) reveal that, in the present solutions, polar interactions between carbonate molecules are more important than the self-association of the 1-alkanol or

Figure 2. GE for 1-alkanol (1) + linear organic carbonate (2) systems. Points, experimental results: (b) ethanol (1) + DMC (2),38 T ) 313.15 K; (9) 1-hexanol (1) + DEC (2) (this work), T ) 353.15 K. Solid lines, ERAS calculations using parameters from Tables 5 and 6. Dashed lines, DISQUAC results with interaction parameters from the literature.22

than the cross association between alkanol and carbonate molecules.22 In terms of ERAS, this leads to low KAB and |∆hAB*| values (Table 6). In contrast, the methanol + propylamine system, where strong interactions exist between unlike molecules, is characterized34 by KAB ) 2124 and ∆hAB* ) -46.3 kJ mol-1. On the other hand, GE and HE curves calculated using ERAS are skewed to low mole fractions of the alcohol (Figures 1-4). The observed differences with experimental results (Figures 1-4) may be ascribed to ERAS and cannot represent properly the mentioned strong dipole-dipole interactions between carbonate molecules. These interactions are better represented by DISQUAC. As a consequence, DISQUAC improves ERAS results for GE and HE (Figures 1-4). Strong dipole-dipole interactions are also present in linear organic carbonate + alkane systems. Figure 5 shows DISQUAC HE results for DMC or DEC + nheptane systems at very high temperatures. The agreement with experimental data (not used in the fitting of the interaction parameters25) is good. Azeotropic data at given temperatures are also reproduced in the correct range of pressure and composition. For example, DISQUAC predicts an azeotrope for the DMC (1) + cyclohexane (2) mixture at 346.55 K; Paz ) 106.7 kPa and x1az ) 0.622. The experimental values40 are Paz ) 101.5 kPa and x1az ) 0.621.

4386 Ind. Eng. Chem. Res., Vol. 42, No. 19, 2003

Figure 3. GE for 1-alkanol (1) + linear organic carbonate (2) systems. Points, experimental results: (b) 1-propanol (1) + DMC (2),38 T ) 313.15 K; (9) 1-hexanol (1) + DMC (2) (this work), T ) 363.15 K; (2) 1-hexanol (1) + DEC (2) (this work), T ) 363.15 K. Solid lines, ERAS calculations using parameters from Tables 5 and 6. Dashed lines, DISQUAC results with interaction parameters from the literature.22

Figure 4. HE for 1-alkanol (1) + DMC (2) systems at 313.15 K. Points, experimental results:38 (b) methanol; (9) ethanol; (2) 1-propanol. Solid lines, ERAS calculations using parameters from Tables 5 and 6. Dashed lines, DISQUAC results with interaction parameters from the literature.22

This is the main advantage of DISQUAC (and of any physical model): they can be applied to any type of mixture. ERAS can be used only when the thermodynamic properties of the systems are mainly determined by the self-association of one component or by cross associations between components. However, it is possible to obtain accurate information on excess molar volumes using ERAS (Figure 6). 5. Conclusions P-x measurements at 353.15 and 363.15 K for 1-hexanol + DMC or + DEC systems are reported. The deviations between the experimental GE and HE values and the ERAS results can be ascribed to the existence

Figure 5. HE for the DMC (1) or DEC (1) + n-heptane (2) mixtures. Points, experimental values:49 (b) system with DMC at T ) 363.15 K and P ) 15.48 bar; (9) system with DEC at T ) 373.15 K and P ) 14.79 bar. Solid lines, DISQUAC calculations with the interaction parameters from literature.25

Figure 6. VE for 1-alkanol (1) + DEC (2) systems at 298.15 K. Points, experimental results: (9) 1-pentanol;51 (b) 1-hexanol.52 Solid lines, ERAS calculations using parameters from Tables 5 and 6. Dashed lines, chemical, VEchem, and physical, VEphys, contributions to VE.

of strong polar interactions between carbonate molecules, not described properly by the model. Acknowledgment JAG gratefully acknowledges the financial support received from the Ministerio de Ciencia y Tecnologı´a “Programa Nacional de Procesos y Productos Quı´micos” (Project PPQ2001-1664) y Unio´n Europea (FEDER) and by the Consejerı´a de Educacio´n y Cultura de la Junta de Castilla y Leo´n (Project VA039/01) y Unio´n Europea (FSE). Literature Cited (1) Parrish, J. P.; Salvatore, R. N.; Jung, K. W. Perspectives on alkyl carbonates in organic synthesis. Tetrahedron 2000, 56, 8207-8237.

Ind. Eng. Chem. Res., Vol. 42, No. 19, 2003 4387 (2) Martindale, W. The Extra Pharmacopoeia; The Pharmaceutical Press: London, 1989. (3) Annesini, M. C.; De Santis, R.; Kikic, I.; Marrelli, R. Excess enthalpy and T-x data of aromatic-propylene carbonate mixtures. J. Chem. Eng. Data 1984, 29, 39-41. (4) Matsuta, S.; Kato, Y.; Ohta, T.; Kurokawa, H.; Yoshimura, S.; Fuhitami, S. Electron-spin-resonance study of the reaction of electrolytic solutions in the positive electrode for lithium-ion secondary batteries. J. Electron. Soc. 2001, 148, A7-A10. (5) Rivetti, F. The role of dimethyl carbonate in the replacement of hazardous chemicals. C. R. Acad. Sci., Ser. IIc: Chim. 2000, 3, 497-503. (6) Wallington, T. J.; Hurley, M. D.; Ball, J. C.; Straccia, A. M.; Platz, J.; Christensen, L. N.; Sehested, J.; Nielsen, O. J. Atmospheric chemistry of dimethylmethane (CH3OCH2OCH3): kinetics and mechanism of its reaction with OH radicals and fate of the alkoxy radicals CH3OCHO(•)OCH3 and CH3OCH2OCH2O(•). J. Phys. Chem. A 1997, 101, 5302-5308. (7) Pacheco, M. A.; Marshall, C. L. Review of dimethyl carbonate (DMC) manufacture and its characteristics as a fuel additive. Energy Fuels 1997, 11, 2-29. (8) Garcı´a, J.; Lugo, L.; Comun˜as, M. J.; Lo´pez, E. R.; Ferna´ndez, J. Experimental excess volumes of organic carbonate + alkane systems. Estimation of the parameters of the Nitta-Chao model for this kind of binary mixture. J. Chem. Faraday Trans. 1998, 94, 1707-1712. (9) Kehiaian, H. V. Group contribution methods for liquid mixtures: a critical review. Fluid Phase Equilib. 1983, 13, 243252. (10) Kehiaian, H. V. Thermodynamics of binary liquid organic mixtures. Pure Appl. Chem. 1985, 57, 15-30. (11) Cocero, M. J.; Mato, F.; Garcı´a, I.; Cobos, J. C.; Kehiaian, H. V. Thermodynamics of binary mixtures containing organic carbonates. 2. Isothermal vapor-liquid equilibria for dimethyl carbonate + cyclohexane, + benzene, or + tetrachloromethane. J. Chem. Eng. Data 1989, 34, 73-76. (12) Cocero, M. J.; Mato, F.; Garcı´a, I.; Cobos J. C. Thermodynamics of binary mixtures containing organic carbonates. 3. Isothermal vapor-liquid equilibria for diethyl carbonate + cyclohexane, + benzene, or + tetrachloromethane. J. Chem. Eng. Data 1989, 34, 443-445. (13) Cocero, M. J.; Garcı´a, I.; Gonza´lez, J. A.; Cobos, J. C. Thermodynamics of binary mixtures containing organic carbonates. Part VI. Isothermal vapor-liquid equilibria for dimethyl carbonate + normal alkanes. Fluid Phase Equilib. 1991, 68, 151161. (14) Cocero, M. J.; Gonza´lez, J. A.; Garcı´a, I.; Cobos, J. C. Liquid-vapor equilibrium and excess Gibbs energy of diethyl carbonate + normal alkanes (C6, C8, C10). Int. DATA Ser., Sel. Data Mixtures, Ser. A 1991, 2, 130-138. (15) Gonza´lez, J. A.; Garcı´a, I.; Cobos, J. C.; Casanova, C. Thermodynamics of binary mixtures containing organic carbonates. 4. Liquid-liquid equilibria of dimethyl carbonate + selected n-alkanes. J. Chem. Eng. Data 1991, 36, 162-164. (16) Domanska, U.; Szurgocinska, M.; Gonza´lez, J. A. Thermodynamics of binary mixtures containing organic carbonates. 12. LLE and SLE measurements for systems of dimethyl carbonate with long n-alkanes. Comparison with DISQUAC and modified UNIFAC predictions. Ind. Eng. Chem. Res. 2002, 41, 3253-3259. (17) Garcı´a, I.; Cobos, J. C.; Gonza´lez, J. A.; Casanova, C.; Cocero, M. J. Thermodynamics of binary mixtures containing organic carbonates. 1. Excess enthalpies of dimethyl carbonate + hydrocarbons or + tetrachloromethane. J. Chem. Eng. Data 1988, 33, 423-426. (18) Garcı´a, I.; Cobos, J. C.; Gonza´lez, J. A.; Casanova, C. Excess enthalpies of diethyl carbonate + some normal alkanes (C6-C14), + cyclohexane, + methylcyclohexane, + benzene, + toluene, or + tetrachloromethane. Int. DATA Ser., Sel. Data Mixtures, Ser. A 1987, 3, 164-173. (19) Garcı´a de la Fuente, I.; Gonza´lez, J. A.; Cobos, J. C.; Casanova, C. Excess molar volumes for dimethyl carbonate + heptane, decane, 2,2,4-trimethylpentane, cyclohexane, benzene, toluene, or tetrachloromethane. J. Chem. Eng. Data 1992, 37, 535-537. (20) Garcı´a de la Fuente, I.; Gonza´lez, J. A.; Cobos, J. C.; Casanova, C. Excess molar volumes of diethyl carbonate with hydrocarbons or tetrachloromethane at 25 °C. J. Solution Chem. 1995, 24, 827-835.

(21) Domanska, U.; Szurgocinska, M.; Gonza´lez, J. A. Thermodynamics of binary mixtures containing organic carbonates. 11. SLE measurements for systems of diethyl carbonate with long n-alkanes. Comparison with DISQUAC and modified UNIFAC predictions. Fluid Phase Equilib. 2001, 190, 15-31. (22) Gonza´lez, J. A.; Szurgocinska, M.; Domanska, U. Thermodynamics of mixtures containing organic carbonates. Part XIII. Solid-liquid equilibria of long-chain 1-alkanol + dimethyl or diethyl carbonate systems: DISQUAC and ERAS analysis of the hydroxyl/carbonate interactions. Fluid Phase Equilib. 2002, 200, 349-374. (23) Kehiaian, H. V.; Gonza´lez, J. A.; Garcı´a, I.; Cobos, J. C.; Casanova, C.; Cocero, M. J. Prediction of vapour-liquid and liquid-liquid equilibria and of enthalpies of mixing in linear carbonates + n-alkane or + cyclohexane mixtures using DISQUAC. Fluid Phase Equilib. 1991, 64, 1-11. (24) Kehiaian, H. V.; Gonza´lez, J. A.; Garcı´a, I.; Cobos, J. C.; Casanova, C.; Cocero, M. J. Steric and inductive effects in binary mixtures of organic carbonates with aromatic hydrocarbons or tetrachloromethane. Fluid Phase Equilib. 1991, 69, 81-89. (25) Gonza´lez, J. A.; Garcı´a de la Fuente, I.; Cobos, J. C.; Casanova, C.; Kehiaian, H. V. Calorimetric and phase equilibrium data for linear carbonates + hydrocarbons or + CCl4 mixtures. Comparison with DISQUAC predictions. Thermochim. Acta 1993, 217, 57-69. (26) Heintz, A. A new theoretical approach for predicting excess properties of alkanol/alkane mixtures. Ber. Bunsen-Ges. Phys. Chem. 1985, 89, 172-181. (27) Rogalski, M.; Malanowski, S. Ebulliometers modified for the accurate determination of vapor-liquid equilibrium. Fluid Phase Equilib. 1980, 5, 97-103. (28) Sporzynski, A.; Gregorowicz, J. VII International Meeting on Boron Chemistry, IME BORON VII, Torun, Poland, 1990. (29) Hala, E.; Pick, J.; Fried, V.; Vilim, O. Vapor-Liquid Equilibrium; Pergamon Press: Oxford, 1967. (30) Barker, J. A. Determination of the activity coefficients from total pressure measurements. Aust. J. Chem. 1953, 6, 207-210. (31) Hayden, J. G.; O’Connell, J. P. A generalized method for predicting second virial coefficients. Ind. Eng. Chem. Process Des. Dev. 1975, 14, 209-216. (32) Renon, H.; Prausnitz, J. M. On the thermodynamics of alcohol-hydrocarbon solutions. Chem. Eng. Sci. 1967, 22, 299307. (33) Flory, P. J. Statistical thermodynamics of liquid mixtures. J. Am. Chem. Soc. 1965, 87, 1833-1838. (34) Heintz, A.; Papaioannou, D. Excess enthalpies of alcohol + amine mixtures. Experimental results and theoretical description using the ERAS model. Thermochim. Acta 1998, 310, 6976. (35) Bender, M.; Heintz, A. Thermodynamics of 1-alkanol + n-alkane mixtures based on predictions of the ERAS model. Fluid Phase Equilib. 1993, 89, 197-215. (36) Funke, H.; Wetzel, M.; Heintz, A. New applications of the ERAS model. Thermodynamics of amine + alkane and alcohol + amine mixtures. Pure Appl. Chem. 1989, 61, 1429-1439. (37) Allen, G.; Chai, Z.; Chong, C. L.; Higgins, J. S.; Tripathi, J. Thermodynamics of oligomeric binary mixtures of polyethylene glycol and propylene glycol methyl ethers. Polymer 1984, 25, 239244. (38) Comelli, F.; Francesconi, R. Isothermal vapor-liquid equilibria measurements, excess molar enthalpies, and excess molar volumes of dimethyl carbonate + methanol, + ethanol, and + propan-1-ol. J. Chem. Eng. Data 1997, 42, 705-709. (39) Bondi, A. Physical Properties of Molecular Crystals, Liquids and Glasses; Wiley: New York, 1968. (40) Li, J.; Gmehling, J. Binary azeotropic data at different pressures for systems with 2-ethoxyethanol, 2-methyl-1-butanol and dimethyl carbonate. 2. J. Chem. Eng. Data 1998, 43, 230232. (41) Lide, D. R.; Kehiaian, H. V. CRC Handbook of Thermophysical and Thermochemical Data; CRC Press: Boca Raton, FL, 1994. (42) Francesconi, R.; Castellari, C.; Lunelli, B.; Malta, V.; Ottani, S.; Comelli, F. Liquid-vapor equilibria and excess Gibbs energy of 1,3-dioxolane + some organic compounds. Int. DATA Ser., Sel. Data Mixtures, Ser. A 1997, 25, 197-220. (43) Luo, H.-P.; Zhou, J.-H.; Xiao, W.-D.; Zhu, K.-H. Isobaric vapor-liquid equilibria of binary mixtures containing dimethyl

4388 Ind. Eng. Chem. Res., Vol. 42, No. 19, 2003 carbonate under atmospheric pressure. J. Chem. Eng. Data 2001, 46, 842-845. (44) Riddick, J. A.; Bunger, W. B.; Sakano, T. K. In Organic Solvents. Physical Properties and Methods of Purification, Techniques of Chemistry; Weissberger, A., Ed.; John Wiley & Sons: New York, 1986; Vol. II. (45) Reid, R. C.; Prausnitz, J. M.; Poling, B. E. The Properties of Gases and Liquids, 4th ed.; McGraw-Hill, New York, 1987. (46) McClellan, A. L. Tables of Experimental Dipole Moments; Rahara Enterprises: El Cerrito, CA, 1974. (47) Lo´pez, E. R.; Lugo, L.; Comun˜as, M. J. P.; Garcı´a, J.; Ferna´ndez, J. Excess molar volumes and excess molar heat capacities of (dimethyl carbonate or diethyl carbonate + n-heptane) at several temperatures. J. Chem. Thermodyn. 2000, 32, 743754. (48) Letcher, T. M.; Naicker, P. K. Excess molar enthalpies and excess molar volumes of (an alkanol + a nitrile compound) at T ) 298.15 K and P ) 0.1 MPa. J. Chem. Thermodyn. 2001, 33, 10351047.

(49) Heintz, A.; Naicker, P. K.; Verevkin, S. P.; Pfestorf, R. Thermodynamics of alcohol + amine mixtures. Experimental results and ERAS model calculations of the heat of mixing. Ber. Bunsen-Ges. Phys. Chem. 1998, 102, 953-959. (50) Lohmann, J.; Bo¨lts, R.; Gmehling, J. Excess enthalpy data for seven binary systems at temperatures between 50 and 140 °C. J. Chem. Eng. Data 2001, 46, 208-211. (51) Rodrı´guez, A.; Canosa, J.; Tojo, J. Physical properties of binary mixtures (diethyl carbonate + alcohols) at several temperatures. J. Chem. Eng. Data 2001, 46, 1506-1515. (52) Francesconi, R.; Comelli, F. Excess molar enthalpies, densities, and excess molar volumes of diethyl carbonate in binary mixtures with seven n-alcohols at 298.15 K. J. Chem. Eng. Data 1997, 42, 45-48.

Received for review April 9, 2003 Revised manuscript received July 14, 2003 Accepted July 15, 2003 IE0303000