Article pubs.acs.org/jced
Liquid−Liquid Equilibrium of Some Aliphatic Alcohols + Disodium Tartrate + Water Aqueous Two-Phase Systems at 298.15 K Ebrahim Nemati-Kande,† Hemayat Shekaari,*,‡ and Safar A. Jafari§ †
Department of Chemistry, Parsabad Mogan Branch, Islamic Azad University, Parsabad, Iran Department of Physical Chemistry, University of Tabriz, Tabriz, Iran § Department of Chemistry, University of Mohaghegh Ardabili, Ardabil, Iran ‡
S Supporting Information *
ABSTRACT: In the present work, the liquid−liquid equilibrium of 1-propanol, 2-propanol, 2-methyl-2-propanol, or 2butanol + disodium tartrate + water aqueous two-phase systems was studied. The experimental binodal curves and tie-line compositions at 298.15 were reported, and the effect of temperature on the phase separation ability of these systems was studied using cloud-point data as a function of alcohol mole fractions at the (293.15 to 323.15) K temperature range with 5 K successive intervals. The effective excluded volume (EEV) model was also was used to describe the salting-out ability in the studied systems. A simple three-parameter empirical equation was successfully used for the correlation of the binodal data, and the modified electrolyte Wilson model for mixed solvent electrolyte systems was used for the correlation of the tie-line compositions. The restricted binary interaction parameters were also reported. Good agreement between the experimental and the calculated tie-line compositions was observed.
■
INTRODUCTION The mixed solvent system in the presence of an added electrolyte is an attractive field to study. When the concentration of the added salt exceeds a critical criterion, the one-phase mixed solvent system becomes an immiscible biphasic system, so that the concentration of the one of the solvents is more than the other, in each of the phases. If one of the phases is water, this system known as an aqueous two-phase system (ATPS). Several types of the ATPS's have been introduced, and the experimental and theoretical investigation of the phase equilibrium conditions in such ATPS's is extensively studied due to their applications in the recovery and purification of chemicals or biological materials.1−3 In recent years several research groups have focused on the measurement and thermodynamic investigation of the ATPS's composed of an aqueous solution of a short chain aliphatic alcohol in the presence of an electrolyte. In this regard, liquid− liquid equilibrium (LLE) of this type of ATPS's in the presence of sodium slats such as sodium chloride,4,5 sodium bromide,6 sodium citrate,7 sodium dihydrogen phosphate,8 sodium carbonate,9 and some others have been investigated by several authors. Several types of organic and inorganic salts were used; however, the use of nontoxic and biodegradable materials to form an ATPS is one of the favorite branches of these studies. Disodium tartrate is a biodegradable and nontoxic salt and, therefore, can be used as a proper and green substitute for traditional inorganic salts. As far as we know, there is no report on the LLE of aliphatic alcohols and aqueous solution of disodium tartrate salt. There are only LLE data for the © 2012 American Chemical Society
polyethylene glycol 4000 + disodium tartrate + water at different temperatures,10 and therefore the study of the ATPS's composed of different alcohols in the presence of disodium tartrate salt can give some important information about the physicochemical properties of these systems. Furthermore, the thermodynamic investigation of the LLE data using reliable models in such ATPS's is an important sight of the studies in these systems. Different types of the local composition based models such as the nonrandom two-liquid (NRTL)11 and electrolyte-NRTL12 models or the group contribution based models such as universal quasichemical (UNIQUAC)13 or universal functional (UNIFAC)14 activity coefficient models have been used to represent the LLE data in alcohol + salt + water systems.15−21 Also, in a previous work22 we generalized the segment-based electrolyte Wilson model to the mixed solvent electrolyte systems and used this model to correlate the liquid−liquid equilibrium of the some aliphatic alcohols + sodium thiosulfate + water ATPS's. This paper is one of our studied ATPS's in which the LLE of 1-propanol, 2-propanol, 2-methyl-2-propanol, or 2-butanol + disodium tartrate + water ternary systems was studied, and the experimental binodal and tie-line data at 298.15 were reported. Also, the effect of temperature on the investigated systems was discussed using the measured cloud-point data at different alcohol mole fractions and in the (293.15 to 323.15) K Received: May 11, 2012 Accepted: July 13, 2012 Published: July 23, 2012 2336
dx.doi.org/10.1021/je300533r | J. Chem. Eng. Data 2012, 57, 2336−2342
Journal of Chemical & Engineering Data
Article
Table 1. Physicochemical Properties of the Pure Chemicals Used in This Work M
purity chemical
CAS No.
source
mass fraction
1-propanol 2-propanol 2-methyl-2-propanol 2-butanol Na2C4H4O6·2H2O H2Of
71-23-8 67-63-0 75-65-0 78-92-2 868-18-8 7732-18-5
Rankem (India) Rankem (India) Lobachemie (India) Lobachemie (India) Riedel-Dehaen (Germany) Ghatreh (Iran)
>0.995 >0.997 >0.990 >0.990 >0.990 >0.999
a
30 b
27 c
kg·mol
εa
d −1
0.060096 0.060096 0.074123 0.074123 0.194052e 0.018015
−3
kg·m
2 −1
C ·J ·m−1
799.54b 781.10b 784.30c 803.35d
20.18 19.85 12.47 15.90
997.04a
78.30
28 d
n0w
1.33250g
29 e
Taken from Lide. Taken from Pang et al. Taken from Rajagopal and Chenthilnath. Taken from Resa et al. The molar mass of anhydrous disodium tartrate. fThe specific conductance of the double-distilled deionized water was about 0.70 μS·cm−1. gThe refractive index of pure water at 298.15 K was taken from Reichardt.33
samples of the both phases (i.e., top and bottom) of several feed samples was measured, using a refractometer (Atago, model DR-A1, Japan) with an uncertainty of the ± 0.0002 in the refractive index measurement, at one hour periods. Periodic measurements show that the necessary rest time to ensure the thermodynamic equilibrium is about 4 h. However, the feed samples were immersed in the water bath for about (6 to 8) h to enrich the equilibrium condition. The split phases were separated using long needle syringes and prepared by diluting for refractive index measurement. The concentration of disodium tartrate in the separated phase samples was determined using a flame photometer (Jenway model PFP7, U.K.). The gravimetric analyses reveal that the uncertainty of the salt concentration using this method was better than ± 0.0038 (in mass fraction). The refractive index measurement was performed to determine the alcohol concentration of the both split phases. In this regard, the refractive indices of known solutions of the ternary alcohol (m) + disodium tartrate (ca) + water (w) systems in the mass fraction range of 0 ≤ wm ≤ 0.1 and 0 ≤ wca ≤ 0.05 were measured at 298.15 K to found a proper relation between the refractive index and alcohol concentration. A satisfactory result was obtained when the experimental refractive index data was fitted to the following simple relation:
temperature range with 5 K successive intervals. The phase separation ability of the studied systems was discussed, and the effective excluded volume (EEV) model developed by Guan et al.23 was used to describe the salting-out ability in the studied systems. Moreover, the modified segment based Wilson model (e-Wilson) model was successfully used for the correlation of the studied ATPS's.
■
EXPERMENTAL SECTION Chemicals. The physicochemical properties of the used chemicals were described in Table 1. Apparatus and Procedure. The cloud-point titration method was performed to collect the binodal curve data. In this method, an appropriate amount of aqueous solution of disodium tartrate solution or alcohol was placed in a doublewall glass cell, and the solution was stirred using a magnetic stirrer. The water at constant temperature was circulated between the walls of the double-wall cell to control the temperature of the cell. The temperature was controlled with an accuracy of ± 0.03 K using a thermostat (JULABO model ED, Germany). After the necessary rest time to establish the constant temperature, the droplets of aqueous solution of another component (i.e., alcohol, or salt) were added to the cell using a normal syringe, until the solution appeared cloudy. This point indicates that the system is in the biphasic region. Subsequently, the tiny droplets of the double-distilled water were added to the cloudy solution watchfully until the cloudiness was vanished. This point indicates a node on the binodal curve. The mass changes were measured by an analytical balance (Sartorius model TE214S, Switzerland) and used to calculate the composition of the alcohol and salt in binodal curve. The precision of the mass balance was ± 1·10−7 kg. The procedure was repeated at least five times, and the uncertainty of the obtained binodal data was found to be better than ± 0.0032 (in mass fraction). To determine the tie-line compositions, appropriate amounts of the concentrate solutions of the salt and the pure alcohol were mixed in glass cells and diluted by adding doubly distilled deionized water to form adequate feed samples (about 10 cm3) which are in the biphasic region. These samples were shaken (2400 cycles·min−1) twice using a shaker (Labtron model LS100, Iran) for 3 min. After the first shaking, the samples were immersed in a thermostatted water bath at a constant temperature of 298.15 K for about an hour. Afterward, the samples were shaken for the second time and placed in the same bath to reach the equilibrium. As we know, in the equilibrium condition any macroscopic property of the systems is stable, and therefore to ensure the occurrence of the thermodynamic equilibrium the refractive index of some
nD = n w0 + amwm + acawca
(1)
In this relation nD and n0w are the refractive indices of the ternary solution and pure water at 298.15 K, respectively. Also, am and aca are the constants and are acquired from the fitting of the experimental refractive indices of the standard solution to eq 1. These constants along with the relative standard deviations are reported in Table 2, and the concentrations of the standard ternary solutions along with the measured refractive indices are given in the Supporting Information tables associated with this article. It is proper to mention that all of the unknown samples were diluted to be in the calibration curve range (i.e., 0 ≤ wm ≤ 0.1 and 0 ≤ wca ≤ 0.05). Also, it was found that the accuracy of the calculation of the alcohol mass fraction using this method is better than ± 0.002. The cloud point titration method was also used to study the effect of temperature on the studied ATPS's. In this regard, an appropriate amount of the aqueous solution of disodium tartrate was titrated with tiny droplets of pure alcohol until the solution was appeared cloudy, and the cell temperature was changed (decreased or increased) at five intervals until the cloudiness disappeared. Afterward, droplets of the alcohol were added to the solution until anew cloudiness of the solution. As can be inferred, in this method the mole fraction of alcohol was 2337
dx.doi.org/10.1021/je300533r | J. Chem. Eng. Data 2012, 57, 2336−2342
Journal of Chemical & Engineering Data
Article
study the phase separation ability in the alcohol + salt + water24 ATPS's. The EEV model for alcohol (m) + salt (ca) + water (w) ternary system has the following form
Table 2. Coefficients of Equation 1 for the Investigated Systems at 298.15 K and Atmospheric Pressurea system
n0w
am
104 SDm
aca
104 SDca
1-propanol (m) + disodium tartrate (ca) + water (w) 2-propanol (m) + disodium tartrate (ca) + water (w) 2-methyl-2-propanol (m) + disodium tartrate (ca) + water (w) 2-butanol (m) + disodium tartrate (ca) + water (w)
1.3325
0.0929
10.12
0.1691
5.56
1.3325
0.0848
3.56
0.1588
1.90
1.3325
0.1046
8.34
0.1659
5.26
1.3325
0.1073
10.28
0.1718
6.42
⎛ w ⎞ w ln⎜V * ca ⎟ + V * m = 0 Mm ⎝ Mca ⎠
(2)
where w and M denote the mass fraction and molecular weight, respectively. Also, V* is the scaled EEV and obtained from the correlation of the binodal data. V* values were calculated by the correlation of the obtained experimental binodal curves using the EEV model and are reported in Table 6 along with the corresponding standard deviations (SDs). Furthermore, the binodal curves were plotted in mole fraction scale in Figure 3 to have a distinct comparison. Figure 3 illustrates that in the studied systems the phaseseparation ability of the alcohols is in the order of: 2-butanol > 2-methyl-2-propanol > 1-propanol > 2-propanol. Also, the data reported in Table 6 demonstrate that the higher salting-out ability of the salt can be related to the greater value of the V* parameter. In other words, for the same salt in the studied systems, the greater value of the V* parameter indicates that the corresponding alcohol is easier to be excluded from the salt-rich phase to the alcohol-rich phase, and therefore the higher phaseseparation ability of alcohols was observed. This, observation is in agreement with the previous studies, in which the larger V* value was attributed to the higher salting-out ability.24 Additionally, the temperature effect on the investigated systems in a larger temperature range was studied by measuring the cloud-point (CP) data at different alcohol mole fractions and constant salt-to-water mole fraction ratios. The exper-
a SDj is the standard deviation between the calculated, cal, and experimental, exp, values of mass fraction, w, for component “j” (i.e., alcohol (m) or salt (ca)) and calculated ones using SDj = [∑i(wcal j,i − 1/2 wexp j,i )/n] . Moreover, n is the number of measured refractive indices data.
changed, whereas the relative salt to water mole fraction ratio remained constant.
■
RESULTS AND DISCUSSION The experimental binodal, tie-line, and cloud-point compositions for the studied ATPS's at 298.15 are listed in Tables 3, 4, and 5, respectively. Additionally, the phase diagrams of the ATPS's composed of 1-propanol or 2-butanol alcohols were plotted in Figures 1 and 2, as examples. Guan et al.23 developed the EEV model based on the statistical geometry methods and recently used this model to
Table 3. Binodal Curve Data for Alcohol (m) + Disodium Tartrate (ca) + Water (w) Ternary Systems as a Function of Mass Fractions at 298.15 Ka and Atmospheric Pressure 100 wm
a
100 wca
100 wm
12.1 15.1 18.6 21.9 26.3
12.2 10.6 8.9 7.5 6.2
30.9 34.3 36.9 39.3 41.3
24.0 25.4 26.4 27.2 28.4
11.6 10.6 10.1 9.6 8.8
29.7 31.2 32.8 35.4 37.1
7.2 8.5 9.9 12.3 13.8 15.3
14.7 13.4 12.1 10.3 9.4 8.6
17.6 19.6 22.3 24.7 27.2 29.8
3.1 3.5 3.9 4.3 4.8 5.4
17.0 15.7 14.1 12.9 11.6 10.4
6.1 6.8 7.2 7.9 8.6 9.1
100 wca
100 wm
1-Propanol + Disodium Tartrate + Water 5.1 42.5 4.3 43.6 3.9 44.7 3.4 46.9 3.0 48.4 2-Propanol + Disodium Tartrate + Water 8.2 39.8 7.4 41.2 6.7 42.9 5.7 44.3 5.0 46.2 2-Methyl-2-propanol + Disodium Tartrate + Water 7.5 31.9 6.8 33.8 5.8 35.6 5.2 37.8 4.6 39.6 4.0 41.4 2-Butanol + Disodium Tartrate + Water 8.9 10.0 7.8 10.8 7.1 11.5 6.1 11.9 5.3 12.8 4.8 12.4
100 wca
100 wm
100 wca
2.8 2.6 2.4 2.1 1.9
49.8 51.4 53.3
1.7 1.5 1.4
4.1 3.7 3.3 2.9 2.5
47.5 49.2 50.4 51.1
2.2 2.0 1.8 1.7
3.6 3.3 3.1 2.8 2.5 2.2
42.9 44.8 46.6
2.0 1.8 1.6
3.9 3.2 2.7 2.4 1.8 2.1
13.3 13.5 14.1 14.6 14.9
1.6 1.4 1.2 0.9 0.8
Standard uncertainties for mass fraction and temperature were found to be better than ± 0.0032 and ± 0.03 K, respectively. 2338
dx.doi.org/10.1021/je300533r | J. Chem. Eng. Data 2012, 57, 2336−2342
Journal of Chemical & Engineering Data
Article
Table 4. Cloud-Point (CP) Data for the Alcohols (m) + Disodium Tartrate (ca) + Water (w) Systems as a Function of Mole Fraction of the Relevant Alcohol in the Temperature Range (293.15 to 328.15) K Ta/K
293.15
298.15
xmc
0.099
0.094
xm
0.144
0.148
xm
0.069
0.061
xm
0.027
0.024
303.15
308.15
313.15
318.15
1-Propanol (m) + Disodium Tartrate (ca) + Water (w) (xca/xw = 0.00886)b 0.089 0.087 0.087 0.087 2-Propanol (m) + Disodium Tartrate (ca) + Water (w) (xca/xw = 0.00885) 0.150 0.151 0.154 0.153 2-Methyl-2-propanol (m) + Disodium Tartrate (ca) + Water (w) (xca/xw = 0.00883) 0.055 0.049 0.044 0.042 2-Butanol (m) + Disodium Tartrate (ca) + Water (w) (xca/xw = 0.00885) 0.024 0.022 0.021 0.020
323.15
328.15
0.087
0.087
0.151
0.148
0.038
0.035
0.020
0.020
The uncertainty of temperature control was better than ± 0.03 K. bStandard uncertainty of the salt to water mole fraction rations (xca/xw) was found to be better than ± 0.00004. cStandard uncertainty of alcohol mole fractions (xm) was found to be better than ± 0.001. a
Table 5. Tie-Line Data for Alcohol (m)a + Disodium Tartrate (ca)b + Water (w) Systems as a Function of Mass Fraction at 298.15 Kc and Atmospheric Pressure total composition 100 wm
100 wca
top phase 100 wm
100 wca
bottom phase 100 wm
100 wca
1-Propanol (m) + Disodium Tartrate (ca) + Water (w) 33.7 5.5 50.6 1.5 16.2 9.5 34.6 6.4 55.0 1.1 13.1 12.2 35.5 7.4 60.5 0.6 11.3 12.0 35.2 9.0 64.8 0.3 9.1 16.6 37.3 10.3 68.1 0.1 6.1 20.5 2-Propanol (m) + Disodium Tartrate (ca) + Water (w) 30.6 9.7 44.9 2.5 11.3 19.1 32.6 9.8 48.9 1.9 9.5 20.7 32.8 11.2 53.5 1.3 8.0 23.0 2-Methyl-2-propanol (m) + Disodium Tartrate (ca) + Water (w) 27.3 6.1 55.1 0.8 15.2 8.4 28.1 6.5 58.0 0.7 14.0 9.2 29.1 6.0 59.4 0.7 12.1 10.6 30.5 7.7 61.9 0.6 9.8 12.5 31.5 8.4 64.3 0.4 7.9 14.1 33.0 9.6 67.7 0.4 5.6 16.8 2-Butanol (m) + Disodium Tartrate (ca) + Water (w) 32.1 1.9 73.2 0.1 12.0 2.8 33.9 3.1 75.7 0.1 10.0 4.9 35.9 4.0 77.9 0.1 7.9 6.7 38.0 4.9 78.2 0.1 7.0 8.5 40.0 6.2 79.5 0.1 5.4 11.7 42.0 7.2 80.3 0.1 3.9 14.3
Figure 1. Experimental and calculated phase diagram for the 1propanol (m) + disodium tartrate (ca) + water (w) system at 298.15 K. ⧫, experimental binodal curve; ---, calculated binodal curve using eq 3; ○, experimental tie-line data; ---×---, calculated tie-line data using generalized Wilson model; ●, initial total compositions.
a
Standard uncertainty of the mass fraction of alcohols using eq 1 was better than ± 0.003. bStandard uncertainty of the mass fraction of disodium tartrate was better than ± 0.002. cThe uncertainty of temperature control was better than ± 0.03 K.
imental cloud-point data at (293.15 to 323.15) K temperature range with successive 5 K intervals reported in Table 4 and plotted in Figure 4 show the alcohol concentration dependence of CP for the same concentration of aqueous disodium tartrate solution for each of the studied systems. As shown in Figure 4, in the case of ATPS's composed of 1-propanol, 2-methyl-2propanol, or 2-butanol, the concentration of alcohol required to achieve a phase separation slightly decreases with increasing temperature, and the phase-separation ability of these ATPS's increased with increasing the temperature. Whereas, in the case of the 2-propanole + disodium tartrate + water system, the concentration of required alcohol increased in the temperature range (293.15 to 313.15) K, at temperatures more than 313.15
Figure 2. Experimental and calculated phase diagram for 2-butanol (m) + disodium tartrate (ca) + water (w) system at 298.15 K. ⧫, experimental binodal curve; ---, calculated binodal curve using eq 3; ○, experimental tie-line data; ---×---, calculated tie-line data using generalized Wilson model; ●, initial total compositions.
K the increase of the temperature was reflected by a decrease in the concentration of required alcohol in the studied temperature range. In other words, the temperature 313.15 K can be considered as an exchange point for the phase separation ability of the 2-propanol + disodium tartrate + water ATPS. It is 2339
dx.doi.org/10.1021/je300533r | J. Chem. Eng. Data 2012, 57, 2336−2342
Journal of Chemical & Engineering Data
Article
noticeable that the temperature has no sensible effect on the alcohol mole fraction for the ATPS's composed of 1-propanol in the temperatures more than about 308.15 K and for the ATPS's composed of 2-butanol at temperatures more than 318.15 K. Furthermore, the results show that the alcohol mole fraction required for phase-separation in the temperature range (293.15 to 328.15) K is in the order of: 2-propanol > 1propanol > 2-methyl-2-propanol > 2-butanol, which is in agreement with hydrophilic series. This trend is similar to the one reported previously25 for 1-propanol, 2-propanol, 2methyl-2-propanol, or 2-butanol + dipotassium oxalate + water systems. As can be inferred from Table 6, the correlation ability of the EEV model is relatively poor, and therefore, the following simple empirical three-parameter equation was used for better representation of the studied binodal curves.
Table 6. Values of Parameters of the One-Parameter EEV Model (eq 2) and Empirical Equation (eq 3) Used for the Correlation of the Experimental Binodal Data at 298.15 K EEV model (eq 2) system
V*
SDa
1-propanol + ca + w 2-propanol + ca + w 2-methyl-2-propanol + ca + w 2-butanol + ca + w
414.7 383.86 542.18 1194.54
3.25 1.15 3.43 2.23
eq 3 system
a
b
c
SDa
1-propanol + ca + w 2-propanol + ca + w 2-methyl-2-propanol + ca + w 2-butanol + ca + w
−0.0594 −0.3337 −0.1041 −0.3472
−0.0840 −0.2569 −0.0926 −0.1442
0.0365 0.3476 0.1078 0.5402
0.06 0.05 0.06 0.06
cal 0.5 SD = ((∑i(100wexp m,i − 100wm,i))/N) , where wm represent the mass fraction of relevant alcohol, N is the number of binodal data, and also superscripts “exp” and “cal” stand for the experimental and calculated values, respectively. a
wca = a + b·ln(wm) + c·wm
(3)
In eq 3 wca and wm denote the mass fraction of salt and alcohol in the binodal curve, respectively, and a, b, and c are fitting parameters. The binodal curves of the studied systems were correlated using nonlinear least-squares regression method to eq 3, and the obtained parameters and the consequent SDs are reported in Table 6. Furthermore, Figures 1 and 2 compare the experimental and calculated binodal curves for ATPS's composed of 1-propanol and 2-butanol alcohols, as examples. The obtained SD and the results shown in Figures 1 and 2 reveal that eq 3 can accurately represent the obtained binodal curves. The generalized Wilson model22 for mixed solvent electrolyte systems (e-Wilson) were also used to represent the LLE of the studied some alcohol + salt + water ATPS's. The model development for the e-Wilson model has been described in detail previously.22 In this work, we only report the result of correlation using the e-Wilson model. For the correlation of the tie-line data, we used the value of ρ = 14.9.26 Densities and dielectric constants of water and alcohols were obtained from other references27−30 at 298.15 K and reported in Table 1. Following the previous work22 the C parameter of the e-Wilson model was treated as a fixed value, and the value of C = 10 was used. The osmotic coefficient data for disodium tartrate + water binary systems at 298.15 K reported by Zafarani-Moattar et al.10 was used to obtain the salt−water, Hw,ca, and water−salt, Hca,w, binary interaction parameters using the Levenberg− Marquardt optimization algorithm. The obtained salt−water and water−salt binary interaction parameters along with the standard deviation are reported in Table 7. Also, the vapor− liquid equilibrium data data for 1-propanol + water and 2propanol + water at 298.15 K reported by Gmehling et al.31 and Tsuji et al.32 were used to obtain the alcohol−water, Hm,w, and water−alcohol, Hw,m, binary interaction parameters, respectively, and also are given in Table 7. The reported SD values confirm that the ability of the e-Wilson model for the correlation of the binary osmotic coefficient or vapor−liquid equilibrium data is very good. It is noticeable that we cannot find any binary data at 298.15 K for the other remaining alcohols, and therefore, in the cases of 2-methyl-2propanol and 2-butanol alcohols the alcohol− water and water−alcohol interaction parameters were obtained from the correlation of the LLE data. The obtained parameters from the correlation of the binary data were fixed for the studied systems, and the following procedure was completed to
Figure 3. Comparison between the experimental binodal curves of the alcohol (m) + disodium tartrate (ca) + water (w) ATPS's at T = 298.15 K. ▲, 2-propanol + ca + w; ◊, 1-propanol + ca + w; ●, 2-methyl-2-propanol + ca + w; △, 2-butanol + ca + w.
Figure 4. Effect of temperature on cloud point, CP, as a function of the alcohol (m) mole fractions, in the presence of aqueous solution of disodium tartrate (ca) salt: ○, 2-propanol; ▲, 1-propanol; □, 2-methyl-2-propanol; ●, 2-butanol.
2340
dx.doi.org/10.1021/je300533r | J. Chem. Eng. Data 2012, 57, 2336−2342
Journal of Chemical & Engineering Data
Article
Table 7. Values of Restricted Parameters of the e-Wilson Model for the Studied Alcohol (m) + Disodium Tartrate (ca) + Water (w) Systems at 298.15 K. The Bold Values Are Obtained from the Correlation of the Binary Aqueous Data system
Hwcaa
Hcawa
104 SDb
Hwm
Hmw
103 SDb
Hcam
Hmca
102 Devc
1-propanol + ca + w 2-propanol + ca + w 2-methyl-2-propanol + ca + w 2-butanol + ca + w
5.5457
0.4393
4.38
0.4997 1.3389 0.7764 0.7702
1.442 0.5808 0.9216 0.9123
8.78 8.57
4.1303 −0.8151 −0.6823 0.4191
−3.6921 3.1303 1.2357 −1.0808
2.63 2.10 0.74 0.10
a
Water−salt and salt−water binary interaction parameters were calculated from the osmotic coefficient data reported by Zafarani-Moattar et al.10 cal 2 0.5 SD = ((∑i(awexp i − awi ) )/N) , where aw represents the activity of water, N is the number of data, and also superscripts “exp” and “cal” stand for exp 2 the experimental and calculated values, respectively. cDev = ∑p∑l∑j((100wcal p,l,j,T − 100wp,l,j,T) /6N), where wp,l,j is the weight fraction of the component j (i.e., alcohol, salt or water) in the phase p for lth tie-line and N represents the number of tie-line data. b
obtain other remaining salt−alcohol, Hca,m, alcohol−salt, Hm,ca, water−alcohol, Hw,m, and alcohol−water, Hm,w, restricted binary interaction parameters from the fitting of tie-line compositions. For multiphase systems at constant temperature and pressure, the chemical potential of any component in each phase, which are in equilibrium, should be equal. The chemical potential of any component at constant temperature and pressure in liquid phases can be rewritten as follows: μi (x) = RT ln(γixi)
ATPS's the higher phase-separation ability of alcohols can be related to the larger EEV value. The measured cloud-point data as a function of the alcohol mole fraction in the temperature range (293.15 to 323.15) K show that the alcohol mole fraction required for phase separation in the temperature range (293.15 to 328.15) K is in the order of: 2-propanol > 1-propanol > 2-methyl-2propanol > 2-butanol, which is in agreement with the hydrophilic series. Additionally, the tie-line compositions at 298.15 K were reported and satisfactorily correlated using the e-Wilson model, and the restricted binary interaction parameters of the e-Wilson model were also reported. Good agreement between the calculated and the experimental tie-line data was observed.
(4)
In eq 4 μi is the chemical potential of component i, and x and γ referred to the mole fraction and activity coefficient, respectively. Also, R and T are the gas constant and absolute temperature, respectively. For the studied ATPS's the equilibrium condition can be reduced as follows: (γixi)top = (γixi)bot
■
* Supporting Information
(5)
Refractive index data (Supplemental Table 1). This material is available free of charge via the Internet at http://pubs.acs.org.
In eq 5 superscripts “top” and “bot” refers to the top and bottom phases, respectively. In this respect, the following objective function (OF) was used to obtain the interaction parameters of the e-Wilson model: OF =
∑∑∑ p
n
k
(xpexp ,n,k
−
ASSOCIATED CONTENT
S
■
AUTHOR INFORMATION
Corresponding Author
*Tel.: 984113393139. Fax: 984113340191. E-mail address:
[email protected] (H.S.).
xpcal, n , k)2 (6)
Notes
where p, n, k, and the “exp” and “cal” subscripts are relative phase (i.e., top or bottom), the number of the relative tie-line, each of the components (i.e., alcohol, salt or water), calculated and experimental values, respectively. The obtained parameters using this method are reported in Table 7 along with the respective deviations (Dev). Also, Figures 1 and 2 compare the calculated and experimental tieline compositions for the ATPS's composed of 1-propanol and 2-butanol alcohols, as examples. The results shown in Figures 1 and 2 and deviations reported in Table 7 show that there is a good agreement between the calculated and the experimental tie-line compositions.
The authors declare no competing financial interest.
■
REFERENCES
(1) Albertsson, P. A. Partitioning of Cell Particles and Macromolecules, 3rd ed.; Wiley-Interscience: New York, 1986. (2) Walter, H.; Brooks, D. E.; Fisher, D. Partitioning in Aqueous Two Phase Systems; Academic Press: New York, 1985. (3) Zaslavsky, B. Y. Aqueous Two-Phase Partitioning, Physical Chemistry and Bioanalytical Application; Marcel Dekker: New York, 1995. (4) De Santis, R.; Marrelli, L.; Muscetta, P. N. Liquid-Liquid Equilibria in Water-Aliphatic Alcohol Systems in the Presence of Sodium Chloride. Chem. Eng. J. 1976, 11, 207−214. (5) Cheluget, E. L.; Marx, S.; Weber, M. E.; Vera, J. H. Equilibrium in Biphasic Aqueous Systems: A Model for the Excess Gibbs Energy and Data for the System H2O−NaCl−1-Propanol at 25 °C. J. Solution Chem. 1994, 23, 275−305. (6) Al-sahhaf, T.; Kapetanovic, E. Salt Effects of Lithium Chloride, Sodium Bromide, or Potassium Iodide on Liquid−Liquid Equilibrium in the System Water + 1-Butanol. J. Chem. Eng. Data 1997, 42, 74−77. (7) Zafarani-Moattar, M. T.; Banisaeid, S.; Beirami, M. A. S. Phase Diagrams of Some Aliphatic Alcohols + Potassium or Sodium Citrate + Water at 25 °C. J. Chem. Eng. Data 2005, 50, 1409−1413. (8) Katayama, H.; Miyahara, M. Liquid−Liquid Phase Equilibria of (Ethanol or Methanol + Water) Containing Either Dipotassium Hydrogen Phosphate or Sodium Dihydrogen Phosphate. J. Chem. Eng. Data 2006, 51, 914−918.
■
CONCLUSIONS In this paper the liquid−liquid equilibrium of 1-propanol, 2propanol, 2-methyl-2-propanol, or 2-butanol + disodium tartrate + water ATPS's was studied at 298.15 K. Using the binodal model of Guan, the EEVs were calculated for the studied systems, and it was shown that the EEV values can be related to the two-phase forming ability of the relevant alcohol. A comparison between the binodal curves, plotted in mole fraction scale, shows that the two-phase formation ability of systems composed of different alcohols is in order of: 2-butanol > 2-methyl-2-propanol > 1-propanol > 2-propanol, and it was found that for a same salt in different alcohol + salt + water 2341
dx.doi.org/10.1021/je300533r | J. Chem. Eng. Data 2012, 57, 2336−2342
Journal of Chemical & Engineering Data
Article
(28) Rajagopal, K.; Chenthilnath, S. Excess Thermodynamic Studies of Binary Liquid Mixtures of 2-Methyl-2-Propanol With Ketones. Indian J. Pure Appl. Phys. 2010, 48, 326−333. (29) Resa, J. M.; González, C.; Juez, M.; de Landaluce, S. O. Density, Refractive Index and Speed of Sound for Mixtures of Ethyl Acetate With 2-Butanol and 3-Methyl-1-Butanol: Vapor−Liquid Equilibrium of the Ethyl Acetate + 3-Methyl-1-Butanol System. Fluid Phase Equilib. 2004, 217, 175−180. (30) Lide, D. R. CRC Handbook of Chemistry and Physics, 87th ed.; Taylor and Francis: Boca Raton, FL, 2007. (31) Gmehling, J.; Onken, U. Vapor−Liquid Equilibrium Data Collection-Aqueous−Organic Systems; Chemistry Data Series, Vol. 1; DECHEMA: Frankfurt, Germany, 1977. (32) Tsuji, T.; Hasegawa, K.; Hiaki, T.; Hongo, M. Isothermal VaporLiquid Equilibria for the 2-Propanol + Water System Containing Poly(Ethylene Glycol) at 298.15 K. J. Chem. Eng. Data 1996, 41, 956− 960. (33) Reichardt, C. Solvents and Solvent Effects in Organic Chemistry, 3rd ed.; Wiley-VCH: Weinheim, 2003.
(9) Salabat, A.; Hashemi, M.; Zafarani-Moattar, M. T. Liquid−Liquid Phase Diagrams of H2O + 2-Butanol + Potassium Phosphate and H2O + 2-Butanol + Na2CO3 Systems at 298.15 K. Phys. Chem. Liq. 2005, 43, 459−465. (10) Zafarani-Moattar, M. T.; Hamzehzadeh, S.; Hosseinzadeh, S. Phase Diagrams for Liquid−Liquid Equilibrium of Ternary Poly(Ethylene Glycol) + Di-Sodium Tartrate Aqueous System and Vapor− Liquid Equilibrium of Constituting Binary Aqueous Systems at T = (298.15, 308.15, and 318.15) K: Experiment and Correlation. Fluid Phase Equilib. 2008, 268, 142−152. (11) Renon, H.; Prausnitz, J. M. Local Composition in Thermodynamic Excess Functions for Liquid Mixtures. AIChE J. 1968, 14, 135− 144. (12) Mock, B.; Evans, L. B.; Chen, C. C. Thermodynamic Representation of Phase Equilibria of Mixed-Solvent Electrolyte Systems. AIChE J. 1986, 32, 1655−1664. (13) Abrams, D. S.; Prausnitz, J. M. Statistical Thermodynamics of Liquid Mixtures: A New Expression for the Excess Gibbs Energy of Partly or Completely Miscible Systems. AIChE J. 1975, 21, 116−128. (14) Fredenslund, A.; Jones, R. L.; Prausnitz, J. M. Group Contribution Estimation of Activity Coefficients in Nonideal Liquid Mixtures. AIChE J. 1970, 21, 1086−1099. (15) Macedo, E. A.; Skovborg, P.; Rasmussen, P. Calculation of Phase Equilibria for Solutions of Strong Electrolytes in Solvent-Water Mixtures. Chem. Eng. Sci. 1990, 45, 875−882. (16) van Bochove, G. H.; Krooshof, G. J. P.; de Loos, T. W. Modelling of Liquid−Liquid Equilibria of Mixed Solvent Electrolyte Systems Using the Extended Electrolyte NRTL. Fluid Phase Equilib. 2000, 171, 45−58. (17) Thomsen, K.; Iliuta, M. C.; Rasmussen, P. Extended UNIQUAC Model for Correlation and Prediction of Vapor−Liquid−Liquid−Solid Equilibria in Aqueous Salt Systems Containing Non-Electrolytes. Part B. Alcohol (Ethanol, Propanols, Butanols)−Water−Salt Systems. Chem. Eng. Sci. 2004, 59, 3631−3647. (18) Pirahmadi, F.; Dehghani, M. R.; Behzadi, B.; Seyedi, S. M.; Rabiee, H. Experimental and Theoretical Study on Liquid−Liquid Equilibrium of 1-Butanol + Water + NaNO3 at 25 and 35 °C. Fluid Phase Equilib. 2010, 299, 122−126. (19) Santos, G. R.; D’avila, S. G.; Aznar, M. Salt Effect of KBr on the Liquid-Liquid Equilibrium of the Water/Ethanol/1-Pentanol System. Braz. J. Chem. Eng. 2000, 17, 721−734. (20) Zafarani-Moattar, M. T.; Nemati-Kande, E.; Soleimani, A. Study of the Liquid−Liquid Equilibrium of 1-Propanol + Manganese Sulphate and 2-Propanol + Lithium Sulphate Aqueous Two-Phase Systems at Different Temperatures: Experiment and Correlation. Fluid Phase Equilib. 2012, 313, 107−113. (21) Nemati-Kande, E.; Shekaari, H. Liquid-Liquid Equilibria of Some Aliphatic Alcohols + Disodium Hydrogen Citrate + Water Ternary Systems at 298.15 K. J. Solution Chem., accepted. (22) Nemati-Kande, E.; Shekaari; Jafari, S. A. Thermodynamic study of aqueous two phase systems for some aliphatic alcohols + sodium thiosulfate + water. Fluid Phase Equilib. 2012, 321, 64−72. (23) Guan, Y.; Lilley, T. H.; Treffry, T. E. A New Excluded Volume Theory and Its Application to the Coexistence Curves of Aqueous Polymer Two-Phase Systems. Macromolecules 1993, 26, 3971−3979. (24) Wang, Y.; Hu, S.; Yan, Y.; Guan, W. Liquid−Liquid Equilibrium of Potassium/Sodium Carbonate + 2-Propanol/Ethanol + Water Aqueous Two-Phase Systems and Correlation at 298.15 K. CALPHAD: Comput. Coupling Phase Diagrams Thermochem. 2009, 33, 726−731. (25) Shekaari, H.; Sadeghi, R.; Jafari, S. A. Liquid-Liquid Equilibria for Aliphatic Alcohols + Dipotassium Oxalate + Water. J. Chem. Eng. Data 2010, 55, 4586−4591. (26) Simonson, J. M.; Pitzer, K. S. Thermodynamics of Multicomponent, Miscible Ionic Systems: the System Lithium NitratePotassium Nitrate-Water. J. Phys. Chem. 1986, 90, 3009−3013. (27) Pang, F. M.; Seng, C. E.; Teng, T. T.; Ibrahim, M. H. Densities and Viscosities of Aqueous Solutions of 1-Propanol and 2-Propanol at Temperatures from 293.15 to 333.15 K. J. Mol. Liq. 2007, 136, 71−78. 2342
dx.doi.org/10.1021/je300533r | J. Chem. Eng. Data 2012, 57, 2336−2342
