Article pubs.acs.org/jced
Apparent Molar Volumes and Expansivities of Ionic Liquids [Cnmim]Br (n = 4, 8, 10, 12) in Dimethyl Sulfoxide Huiyong Wang, Jianji Wang,* and Shibiao Zhang School of Chemical and Environmental Sciences, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan 453007, P. R. China ABSTRACT: Densities for solutions of [Cnmim]Br (n = 4, 8, 10, 12) ionic liquids (ILs) in dimethyl sulfoxide (DMSO) have been determined as a function of ionic liquid concentration at the temperature T = (293.15, 298.15, 303.15, 308.15, and 313.5) K and atmospheric pressure. The apparent molar volumes, apparent molar volumes at infinite dilution, and limiting apparent molar expansivities of the ILs have been obtained from the experimental density data. These data were used to understand the effect of the alkyl chain length of the ILs and experimental temperature on the IL−DMSO interactions occurring in the studied solutions. It was shown that the apparent molar volumes at infinite dilution increased with increasing alkyl chain length of the ILs and temperature of the systems. Furthermore, the values of the limiting apparent molar expansibilities were found to be positive and decrease with increasing temperature.
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INTRODUCTION Ionic liquids (ILs) are a family of substances constituted entirely by ions and melt at room temperature. The unique properties of these compounds include a low melting point, high thermal stability, negligible vapor pressure, wide electrochemical window, high solubility for both polar and nonpolar compounds, and highly tunable properties by varying the chemical structures of their cations and anions. This makes ILs potentially useful as “designer solvents”.1 Thus, ILs have found extensive applications in chemical reactions, electrochemistry, biocatalysis, carbon dioxide absorption, biomass dissolution, and separation science.2−7 To better understand the nature of ILs and rationally develop their applications, information about the thermodynamic and thermophysical properties of ILs and their mixtures with molecular compounds is essential. To date, a number of works have been reported for the physicochemical properties of ILs and their mixtures with molecular compounds such as density, conductivity, viscosity, heat capacity, enthalpy, surface tension, and refractive index.8−15 However, only a few papers are focused on the limiting molar quantities which are obtained from the dilution solution region of ILs. Practically, these limiting molar quantities, such as apparent molar volumes at infinite dilution and limiting apparent molar expansivities, are very important for the investigation of interactions between ILs and molecular compounds and for the design of process engineering involving ILs. In this work, densities for solutions of 1-alkyl-3-methylimidazolium bromine [Cnmim]Br (n = 4, 8, 10, 12) in dimethyl sulfoxide (DMSO) have been measured at the temperature T = (293.15 to 313.5) K with an interval of 5 K and atmospheric pressure. From these data, apparent molar volumes, apparent molar volumes at infinite dilution, and limiting apparent molar expansivities of the ILs in DMSO have been reported. The results are used to examine the effect of alkyl chain length of the cations on volumetric properties of the ILs and to understand the interactions of the ILs with DMSO in the binary solutions. © 2012 American Chemical Society
EXPERIMENTAL SECTION Chemicals. 1-Methylimidazole (99 %) was obtained from Shanghai Chem. Co. 1-Bromobutane (99 %), 1-bromooctane (99 %), 1-bromodecane (99 %), and 1-bromododecane (99 %) were purchased from Alfa Aeser, which were distilled before use. Dimethyl sulfoxide (99.5 %) from Tianjin Kermel Chem. Co. was dried over 0.4 nm molecular sieves (Fluka) and afterward distilled before use. The water content in DMSO was less than 100 ppm. [Cnmim]Br (n = 4, 8, 10, 12) were synthesized and purified by the procedure described in the literature.16,17 These ILs were dried under vacuum at 343 K for at least two days in the presence of P2O5 prior to measurement. The mass fraction purities of all of the ILs were greater than 99.8 %. The water content in the ILs determined by Karl Fischer titration was less than 0.02 wt %. Apparatus and Procedure. Stock solutions of the ILs (about 0.04 mol·kg−1) were prepared by mass, and then diluted by DMSO to get the test samples. The concentrations of the ILs for the test samples were less than the critical aggregation concentrations of these ILs in DMSO. The densities of all the samples were measured by using an Anton Paar DMA 60/602 vibrating tube digital densimeter. The temperature in the vibrating tube cell was controlled by a constant-temperature bath (Schott, German) with water as circulating fluid. A CT1450 temperature controller and a CK-100 ultracryostat were used to keep the bath temperature at ± 0.01 K. The apparatus was calibrated periodically, and pure water and air were used for the calibration. The uncertainty in density was estimated to be ± 1·10−5 g·cm−3.
Received: January 18, 2012 Accepted: June 20, 2012 Published: July 2, 2012 1939
dx.doi.org/10.1021/je300017m | J. Chem. Eng. Data 2012, 57, 1939−1944
Journal of Chemical & Engineering Data
Article
Table 1. Densities, ρ, and Apparent Molar Volumes, VΦ, for [Cnmim]Br (n = 4, 8, 10, 12) in DMSO at Different Temperatures [C4mim]Br 3
10 ·m1
ρ
mol·g−1
g·cm3
0 0.004170 0.006430 0.009510 0.01236 0.01500 0.01784 0.02066 0.02307 0.02628 0.02848
[C8mim]Br VΦ
3
10 ·m1
ρ
cm3·mol−1
mol·g−1
g·cm3
1.10022 1.10042 1.10053 1.10068 1.10082 1.10095 1.10109 1.10123 1.10135 1.10151 1.10162
159.49 159.27 159.12 158.95 158.83 158.73 158.61 158.51 158.40 158.33
0 0.002220 0.004110 0.006390 0.008680 0.01098 0.01287 0.01560 0.01754 0.01986 0.02220
1.10022 1.10028 1.10033 1.10039 1.10045 1.10051 1.10056 1.10063 1.10068 1.10074 1.10080
0 0.004160 0.006430 0.009690 0.01254 0.01516 0.01758 0.02039 0.02319 0.02617 0.02856
1.09533 1.09553 1.09564 1.09580 1.09594 1.09607 1.09619 1.09633 1.09647 1.09662 1.09674
159.86 159.73 159.47 159.33 159.17 159.06 158.94 158.82 158.69 158.61
0 0.003697 0.007705 0.01147 0.01568 0.01953 0.02373 0.02785 0.03185 0.03581 0.03956
1.095332 1.095431 1.095536 1.095634 1.095742 1.095840 1.095946 1.096051 1.096150 1.096248 1.096340
0 0.004970 0.008230 0.01126 0.01409 0.01689 0.02008 0.02326 0.02642 0.02917 0.03153
1.09036 1.09060 1.09076 1.09091 1.09105 1.09119 1.09135 1.09151 1.09167 1.09182 1.09194
160.13 159.85 159.62 159.50 159.33 159.18 159.04 158.89 158.77 158.68
0 0.002540 0.005880 0.008880 0.01151 0.01491 0.01758 0.02064 0.02333 0.02681 0.03031
1.09034 1.09041 1.09050 1.09058 1.09065 1.09074 1.09081 1.09089 1.09096 1.09105 1.09114
0 0.00514 0.00817 0.01139 0.01418 0.01696 0.01992 0.02347 0.0264 0.02914 0.03167
1.08541 1.08566 1.08581 1.08597 1.08611 1.08625 1.08641 1.08659 1.08674 1.08688 1.08701
160.29 159.99 159.80 159.61 159.45 159.28 159.13 158.98 158.87 158.77
0 0.002160 0.004710 0.006920 0.009130 0.01398 0.01624 0.01888 0.02155 0.02348 0.02616
1.08541 1.08543 1.08550 1.08556 1.08562 1.08575 1.08581 1.08588 1.08595 1.08600 1.08607
0 0.004890 0.007690 0.010690 0.01325 0.01542 0.01934 0.02264 0.02575
1.08045 1.08070 1.08083 1.08098 1.08111 1.08123 1.08143 1.08160 1.08176
160.42 160.11 159.95 159.73 159.61 159.39 159.20 159.06
0 0.006230 0.01004 0.01351 0.01667 0.01987 0.02275 0.02686 0.02946
1.08043 1.08057 1.08067 1.08076 1.08084 1.08092 1.08099 1.08109 1.08115
[C10mim]Br VΦ
3
10 ·m1
ρ
cm3·mol−1
mol·g−1
g·cm3
293.15 K 0 228.10 0.004020 228.14 0.006490 228.18 0.009330 228.23 0.01163 228.26 0.01410 228.30 0.01670 228.32 0.01877 228.35 0.02117 228.37 0.02341 228.40 0.02766 298.15 Ka 0 228.84 0.005147 229.07 0.008680 229.17 0.01336 229.31 0.01682 229.39 0.02087 229.49 0.02779 229.52 0.03347 229.61 0.04096 229.67 0.04462 229.73 0.05299 303.15 K 0 229.47 0.005420 229.55 0.007290 229.64 0.009690 229.69 0.01151 229.74 0.01339 229.79 0.01545 229.84 0.01741 229.89 0.01809 229.94 0.01996 229.99 308.15 K 0 229.94 0.005010 230.03 0.006760 230.14 0.01153 230.19 0.01415 230.34 0.01624 230.40 0.01840 230.45 0.02101 230.52 0.02330 230.58 230.63 313.15 K 0 231.38 0.004840 231.64 0.007100 231.81 0.009630 232.00 0.01229 232.17 0.01489 232.35 0.01739 232.53 0.01950 232.71 0.02205 1940
[C12mim]Br VΦ
3
10 ·m1
ρ
VΦ
cm3·mol−1
mol·g−1
g·cm3
cm3·mol−1
1.10022 1.10027 1.10030 1.10034 1.10038 1.10041 1.10045 1.10049 1.10053 1.10056 1.10063
264.77 264.45 264.22 263.98 263.85 263.64 263.46 263.35 263.17 263.00
0 0.003970 0.006230 0.008180 0.01037 0.01216 0.01421 0.01656 0.01857 0.02122 0.02403
1.10022 1.10023 1.10024 1.10025 1.10026 1.10026 1.10027 1.10028 1.10029 1.10030 1.10031
298.42 298.33 298.29 298.24 298.19 298.14 298.11 298.08 298.03 298.00
1.095332 1.095402 1.095455 1.095529 1.095585 1.095652 1.095770 1.095870 1.096000 1.096070 1.096220
265.55 265.06 264.57 264.31 264.05 263.66 263.38 263.15 262.94 262.72
0 0.002680 0.004967 0.007868 0.01038 0.01304 0.01600 0.01873 0.02082 0.02457 0.02736
1.095347 1.095355 1.095363 1.095374 1.095384 1.095395 1.095407 1.095419 1.095428 1.095445 1.095458
299.97 299.77 299.59 299.48 299.38 299.32 299.24 299.20 299.11 299.05
1.09037 1.09045 1.09048 1.09052 1.09055 1.09058 1.09061 1.09065 1.09066 1.09069
266.19 266.02 265.62 265.40 265.23 265.09 264.86 264.84 264.60
0 0.003710 0.006140 0.007920 0.009940 0.01180 0.01399 0.01604 0.01817 0.01986 0.02211
1.09038 1.09040 1.09040 1.09041 1.09042 1.09043 1.09044 1.09045 1.09046 1.09047 1.09048
301.12 300.96 300.86 300.70 300.62 300.58 300.46 300.39 300.34 300.24
1.08542 1.08549 1.08552 1.08559 1.08564 1.08568 1.08572 1.08576 1.08580
267.38 267.10 266.51 266.18 265.93 265.71 265.53 265.31
0 0.004360 0.006830 0.009030 0.01149 0.01349 0.01606 0.01812 0.02147 0.02348 0.02922
1.08541 1.08543 1.08543 1.08545 1.08546 1.08547 1.08548 1.08549 1.08551 1.08552 1.08555
302.31 302.12 301.93 301.82 301.69 301.56 301.46 301.37 301.30 301.04
1.08045 1.08052 1.08056 1.08060 1.08065 1.08069 1.08074 1.08078 1.08082
268.13 267.78 267.43 267.01 266.79 266.51 266.36 266.13
0 0.004530 0.006850 0.009070 0.01123 0.01315 0.01625 0.01812 0.02054
1.08047 1.08048 1.08050 1.08051 1.08052 1.08053 1.08055 1.08056 1.08057
303.40 303.12 302.93 302.80 302.64 302.44 302.35 302.22
dx.doi.org/10.1021/je300017m | J. Chem. Eng. Data 2012, 57, 1939−1944
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Table 1. continued [C4mim]Br
a
3
10 ·m1
ρ
mol·g−1
g·cm3
0.02845 0.03154
1.08190 1.08206
[C8mim]Br VΦ
3
10 ·m1
ρ
cm3·mol−1
mol·g−1
g·cm3
158.93 158.81
0.03287 0.03631
1.08123 1.08131
[C10mim]Br VΦ
3
10 ·m1
ρ
cm3·mol−1
mol·g−1
g·cm3
313.15 K 232.87 0.02449 233.01
1.08087
[C12mim]Br VΦ
3
10 ·m1
ρ
VΦ
cm3·mol−1
mol·g−1
g·cm3
cm3·mol−1
265.85
0.02269
1.08059
302.10
Reference 20.
Figure 1. Plots of the apparent molar volume of the ILs as a function of the square root of the ILs concentration in DMSO at different temperatures: (A) [C4mim]Br; (B) [C8mim]Br; (C) [C10mim]Br; (D) [C12mim]Br; ■, 293.15 K; ●, 298.15 K; ▲, 303.15 K; ▼, 308.15 K; ○, 313.15 K.
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In this equation, m is the molality (mol·g−1) of the ILs in DMSO, ρ and ρ0 stand for the densities (g·cm−3) of the solutions and DMSO, respectively, and M is the molar mass (g·mol−1) of the ILs. The calculated apparent molar volumes are also given in Table 1 at T = (293.15 to 313.15) K. The concentration dependence of VΦ values in dilute region at a given temperature and pressure have been described by the empirical linear equation:21
RESULTS AND DISCUSSION Experimental densities for the studied solutions at various temperatures are reported in Table 1 as a function of molality of the ILs. It can be seen that the density values for the binary mixtures of [Cnmim]Br (n = 4, 8, 10, 12) with DMSO decrease with the increasing alkyl chain length of cations of the ILs at a given IL concentration and a given temperature. This trend is very consistent with the finding that density generally decreases with the increase in alkyl chain length of cation or the increase of the anion size documented for ILs.18,19 The apparent molar volumes, VΦ (cm3·mol−1), of the ILs in the binaries were calculated from the solution densities using the following equation: VΦ =
(ρ − ρ0 ) M − ρ mρ0 ρ
VΦ = V 0 Φ + Svm1/2
(2)
where V0Φ is the apparent molar volume at infinite dilution (equals to the standard partial molar volume in value), which is the limiting value of the apparent (or partial) molar volume when their concentration is close to zero. At infinite dilution, the interactions of cations with anions are usually absent.
(1) 1941
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0.09 0.30 0.26 0.22 0.22 ± ± ± ± ± −4.55 −7.87 −9.91 −11.87 −15.40 0.01 0.04 0.03 0.03 0.03 ± ± ± ± ± 298.69 300.32 301.72 303.08 304.41 0.03 0.09 0.05 0.03 0.05 0.29 0.55 0.71 0.40 0.44 ± ± ± ± ± −17.44 −17.70 −23.40 −25.47 −26.00 0.04 0.09 0.08 0.04 0.05 ± ± ± ± ± 265.88 266.68 267.95 269.20 269.96 0.01 0.03 0.01 0.02 0.05 0.06 0.18 0.01 0.14 0.50 ± ± ± ± ± 3.03 6.23 4.24 6.06 14.87 0.01 0.03 0.01 0.02 0.07 ± ± ± ± ± 227.95 228.50 229.23 229.63 230.13 160.17 160.68 161.07 161.30 161.45
0.02 0.02 0.02 0.01 0.02
−10.91 −12.22 −13.44 −14.23 −14.89
± ± ± ± ±
0.14 0.18 0.13 0.10 0.18 ± ± ± ± ± 293.15 298.15 303.15 308.15 313.15
0.01 0.02 0.01 0.01 0.02
cm3·kg1/2·mol−3/2
Sv Sv Φ
cm3·kg1/2·mol−3/2 cm3·kg1/2·mol−3/2
Sv Φ
V Sv
cm3·kg1/2·mol−3/2 cm3·mol−1 T/K
SD
cm3·mol−1
[C8mim]Br
SD
V
0
cm3·mol−1
[C10mim]Br
SD
cm3·mol−1
[C12mim]Br
V0Φ 1942
0
where the intercept a denotes the sum of the apparent molar volume at infinite dilution of 3-methylimidazolium cation and the Br− anion, and the slope, b, stands for the contribution per CH2, V0Φ(CH2), in the alkyl chain of the imidazolium cations to the apparent molar volume at infinite dilution of the ILs in DMSO at a given temperature. Thus obtained values are shown in Table 3. It can be seen that, at each temperature, the standard deviations of a and b are reasonable. However, in the temperature range investigated, the effect of temperature on the coefficients a and b is not significant; hence any temperature dependence cannot be determined definitely. It was also observed that the absolute values of Sv became larger with increasing temperature, suggesting an increased electrostatic interaction between cation and anion of the ILs and a decreased solvation interaction between the ILs and the solvent at higher temperatures. A similar behavior was also observed for 1-ethyl-3-methylimidazolium methyl sulfate, 1-hexyl-3methylimidazolium methyl sulfate, and 1-hexyl-3-methylimidazolium ethyl sulfate in water.25 The temperature dependence of apparent molar volume at infinite dilution can be expressed as the second-order polynomial of the absolute temperature:
[C4mim]Br
(3)
V0Φ
Table 2. Fitting Parameters and Standard Deviations (SD) of Equation 2 for [Cnmim]Br (n = 4, 8, 10, 12) at Different Temperatures
V 0 Φ = a + bnc
SD
Therefore, the apparent molar volume at infinite dilution is a measure for the ion−solvent interactions. On the other hand, the slope, Sv, shows the ion−ion interactions. In general, Sv is positive, but sometimes negative for some electrolytes, particularly for tetraalkylammonium salts.22−24 Values of V0Φ and Sv for the ILs + DMSO systems were obtained at different temperatures by a linear regression analysis (Figure 1), and the results were listed in Table 2 together with their standard deviations and the standard deviations of fit (SD). It was found that apparent molar volumes at infinite dilution for the ILs increase with the increase in the alkyl chain length of the cations at a given temperature, as shown in Figure 2. In addition, the apparent molar volumes at infinite dilution for the ILs also increase with increasing temperature due to the release of DMSO from the loose solvation layer of the ILs. This suggests that solvation of the ILs in DMSO was weakened at higher temperatures. A similar trend was also observed for 1-ethyl-3methylimidazolium methyl sulfate, 1-hexyl-3-methylimidazolium methyl sulfate, and 1-hexyl-3-methylimidazolium ethyl sulfate in aqueous solutions.25 It is interesting to find that the Sv values for [Cnmim]Br (n = 4, 10, 12) are negative but that for [C8mim]Br the value is positive. At first sight, the Sv value of [C8mim]Br in DMSO may be in error. Therefore, we repeatedly measured the solution densities of [C8mim]Br in DMSO and calculated the Sv value of [C8mim]Br. It was found that the Sv value of [C8mim]Br is still positive and the reproducibility is very good. It seems that the data are no problem. Generally speaking, although the Sv values are frequently used as a qualitative measure for the ion−ion interactions, there are many factors affecting the Sv values of electrolyte, such as the nature of electrolyte and solvent, electrolyte concentration, and among others. This means that the Sv value does not have definite physical meaning. Therefore, at the present stage, we cannot give a reasonable explanation for the negative and positive Sv values of the ILs in DMSO. A linear relationship between apparent molar volumes at infinite dilution and the carbon atom number (nc) in the alkyl chains of the ILs is shown in Figure 2. This can be represented by the following equation:
0.01 0.03 0.02 0.02 0.02
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that, at each temperature, EΦ0 values for the ILs in DMSO are positive. This suggests that, on heating, some DMSO molecules may be released from the loose solvation layer of the ions. In addition, the EΦ0 values decrease with increasing temperature. The possible reason is that, at higher temperatures, there are less bound solvent molecules on the ions, so the expansibility of the ILs in solutions becomes weaker.26
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CONCLUSION Experimental density data for the solutions of [Cnmim]Br (n = 4, 8, 10, 12) in DMSO have been measured as a function of IL concentration at different temperatures. From these data, the apparent molar volumes, apparent molar volumes at infinite dilution, and the limiting apparent molar expansibilities of the ILs were reported at different temperatures. It was found that, at a given temperature, the solution densities increased with the increase of the IL concentrations but decreased with alkyl chain length of the ILs, and the apparent molar volumes at infinite dilution increased linearly with the carbon atom number in alkyl chain of the ILs. The values of the limiting apparent molar expansibilities were positive and decreased with the increase of temperature. From the viewpoint of IL−molecular solvent interactions, it may be concluded that, with increasing temperature, the solvation of the ILs was weakened, and hence the ionic interaction was enhanced in DMSO.
Figure 2. Linear plots of the apparent molar volumes at infinite dilution for [Cnmim]Br (n = 4, 8, 10, 12) as a function of the carbon atom number (nc) in the alkyl chain of the ILs at different temperatures: ■, 293.15 K; ●, 298.15 K; ▲, 303.15 K; ▼, 308.15 K; ○, 313.15 K.
Table 3. Fitting Parameters and Standard Deviations of Fit (SD) a/cm3·mol−1
T/K 293.15 298.15 303.15 308.15 313.15
90.2 90.0 89.8 89.3 88.8
± ± ± ± ±
2.4 2.5 2.7 3.1 3.2
b/cm3·mol−1
SD
± ± ± ± ±
1.60 1.62 1.76 2.05 2.08
17.4 17.5 17.7 17.8 18.0
0
0.3 0.3 0.3 0.4 0.4
2
VΦ = A + B(T /K) + C(T /K)
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*E-mail:
[email protected]. Funding
This work was supported by the National Natural Science Foundation of China (Grant No. 21133009), the National Basic Research Program of China (973 Program, No. 2009CB219902), and the Innovation Scientists and Technicians Troop Construction Projects of Henan Province (No. 092101510300) and the foundation of Shanghai Key Laboratory of Green Chemistry and Chemical Processes.
(4)
where A, B, and C are empirical parameters, and their values obtained by regression analysis were listed in Table 4. Table 4. Coefficients of Equation 4 and Standard Deviations of Fit (SD) ILs
A
B
C
SD
[C4mim]Br [C8mim]Br [C10mim]Br [C12mim]Br
−89.28 82.96 176.94 42.35
1.588 0.854 0.387 1.427
−0.00251 −0.00123 −0.000286 −0.00189
0.01 0.08 0.21 0.05
Notes
The authors declare no competing financial interest.
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REFERENCES
(1) Plechkova, N. V. Applications of ionic liquids in the chemical industry. Chem. Soc. Rev. 2008, 37, 123−150. (2) Hallett, J. P.; Welton, T. Room-Temperature Ionic Liquids: Solvents for Synthesis and Catalysis. 2. Chem. Rev. 2011, 111, 3508− 3576. (3) Rantwijk, F. V.; Sheldon, R. A. Biocatalysis in Ionic Liquids. Chem. Rev. 2007, 107, 2757−2785. (4) Lee, S. Y.; Ogawa, A.; Kanno, M.; Nakamoto, H.; Yasuda, T.; Watanabe, M. Nonhumidified Intermediate Temperature Fuel Cells Using Protic Ionic Liquids. J. Am. Chem. Soc. 2010, 132, 9764−9773. (5) King, A. W. T.; Asikkala, J.; Mutikainen, I.; Jarvi, P.; Kilpelainen, I. Distillable Acid−Base Conjugate Ionic Liquids for Cellulose
The limiting apparent molar expansibility EΦ0 measures the variation of limiting apparent molar volume with temperature, its temperature dependence can be described by the equation: EΦ0 = (∂V Φ0 /∂T )p = B + 2CT
AUTHOR INFORMATION
Corresponding Author
(5)
0
The values of EΦ for the studied ILs are given in Table 5 as a function of experimental temperature. It is interesting to note
Table 5. Limiting Apparent Molar Expansivities, EΦ0, of [Cnmim]Br (n = 4, 8, 10, 12) in DMSO at Different Temperatures EΦ0/cm3·mol−1·K−1 IL
T = 293.15 K
T = 298.15 K
T = 303.15 K
T = 308.15 K
T = 313.15 K
[C4mim]Br [C8mim]Br [C10mim]Br [C12mim]Br
0.1164 0.1329 0.2193 0.3189
0.0913 0.1206 0.2165 0.3000
0.0662 0.1083 0.2136 0.2811
0.0411 0.0960 0.2107 0.2622
0.0160 0.0837 0.2079 0.2433
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dx.doi.org/10.1021/je300017m | J. Chem. Eng. Data 2012, 57, 1939−1944
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Dissolution and Processing. Angew. Chem., Int. Ed. 2011, 50, 6301− 6305. (6) Gurkan, B. E.; de la Fuente, J. C.; Mindrup, E. M.; Ficke, L. E.; Goodrich, B. F.; Price, E. A.; Schneider, W. F.; Brennecke, J. F. Equimolar CO2 Absorption by Anion-Functionalized Ionic Liquids. J. Am. Chem. Soc. 2010, 132, 2116−2117. (7) Han, X.; Armstrong, D. W. Ionic Liquids in Separations. Acc. Chem. Res. 2007, 40, 1079−1086. (8) Alvarez, V. H.; Mattedi, S.; Martin-Pastor, M.; Aznar, M.; Iglesias, M. Thermophysical Properties of Binary Mixtures of {Ionic Liquid 2Hydroxyethylammonium Acetate + (Water, Methanol, or Ethanol)}. J. Chem. Thermodyn. 2011, 43, 997−1010. (9) Yu, Z.; Gao, H.; Wang, H.; Chen, L. Densities, Viscosities, and Refractive Properties of the Binary Mixtures of the Amino Acid Ionic Liquid [bmim][Ala] with Methanol or Benzylalcohol at T = (298.15 to 313.15) K. J. Chem. Eng. Data 2011, 56, 2877−2883. (10) Wang, J.; Jiang, H.; Liu, Y.; Hua, Y. Density and Surface Tension of Pure 1-Ethyl-3-methylimidazolium L-lactate Ionic Liquid and Its Binary Mixtures with Water. J. Chem. Thermodyn. 2011, 43, 800−804. (11) Ciocirlan, O.; Croitoru, O.; Iulian, O. Densities and Viscosities for Binary Mixtures of 1-Butyl-3-Methylimidazolium Tetrafluoroborate Ionic Liquid with Molecular Solvents. J. Chem. Eng. Data 2011, 56, 1526−1534. (12) Deenadayalu, N.; Bahadur, I.; Hofman, T. Volumetric Properties for (Ionic Liquid + Methanol or Ethanol or 1-Propanol or Nitromethane) at 298.15 K and Atmospheric Pressure. J. Chem. Eng. Data 2011, 56, 1682−1686. (13) Currás, M. R.; Gomes, M. F. C.; Husson, P.; Padua, A. A. H.; Garcia, J. Calorimetric and Volumetric Study on Binary Mixtures 2,2,2Trifluoroethanol + (1-Butyl-3-methylimidazolium Tetrafluoroborate or 1-Ethyl-3-methylimidazolium Tetrafluoroborate). J. Chem. Eng. Data 2010, 55, 5504−5512. (14) Mokhtarani, B.; Mojtahedi, M. M.; Mortaheb, H. R.; Mafi, M.; Yazdani, F.; Sadeghian, F. Densities, Refractive Indices, and Viscosities of the Ionic Liquids 1-Methyl-3-octylimidazolium Tetrafluoroborate and 1-Methyl-3-butylimidazolium Perchlorate and Their Binary Mixtures with Ethanol at Several Temperatures. J. Chem. Eng. Data 2008, 53, 677−682. (15) García-Miaja, G.; Troncoso, J.; Roman, J. Density and Heat Capacity as a Function of Temperature for Binary Mixtures of 1-Butyl3- methylpyridinium Tetrafluoroborate + Water, + Ethanol, and + Nitromethane. J. Chem. Eng. Data 2007, 52, 2261−2265. (16) Dupont, J.; Consort, C. S.; Saurez, P. A. Z.; Souza, R. F. Preparation of 1-Butyl-3-methyl imimdazolium-based Room Temperature Ionic Liquids. Org. Synth. 1999, 79, 236−243. (17) Holbrey, J. D.; Seddon, K. R. The Phase Behavior of 1-Alkyl-3methylimidazolium Tetrafluoroborates: Ionic Liquids and Ionic Liquid Crystals. J. Chem. Soc., Dalton Trans. 1999, 2133−2140. (18) Wilkes, J. S. Properties of Ionic Liquid Solvents for Catalysis. J. Mol. Catal., A: Chem. 2004, 214, 11−17. (19) Marsh, K. N.; Boxall, J. A.; Lichtenthaler, R. Room Temperature Ionic Liquids and Their Mixtures-A Review. Fluid Phase Equilib. 2004, 219, 93−98. (20) Wang, J.; Zhang, S.; Wang, H.; Pei, Y. Apparent Molar Volumes and Electrical Conductance of Ionic Liquids [Cnmim]Br (n = 8, 10, 12) in Ethylene Glycol, N,N-Dimethylformamide, and Dimethylsulfoxide at 298.15 K. J. Chem. Eng. Data 2009, 54, 3252−3258. (21) Marcus, Y.; Hefter, G. Standard Partial Molar Volumes of Electrolytes and Ions in Nonaqueous Solvents. Chem. Rev. 2004, 104, 3405−3452. (22) Gopal, R.; Siddiqi, M. A. Study of Ion-Solvent Interaction of Some Tetraalkylammonium and Common Ions in N-methylacetamide from Apparent Molal Volume Data. J. Phys. Chem. 1969, 73, 3390− 3394. (23) MacDonald, D. D.; Hyne, J. B. Partial Molal Volume Behavior of Tetraalkylammonium Chlorides in Aqueous Acetone and Aqueous Dimethylsulfoxide. Can. J. Chem. 1970, 48, 2416−2422.
(24) Masterton, W. L.; Welles, H.; Knox, J. H.; Millero, F. J. Volume Change of Ion Pair Formation: Rubidium Nitrate and Thallium(I) Nitrate in Water. J. Solution Chem. 1974, 3, 91−102. (25) Shekaari, H.; Armanfar, E. Apparent Molar Volumes and Expansivities of Aqueous Solutions of Ionic Liquids, l-Alkyl-3methylimidazolium Alkyl Sulfate at T = (298.15−328.15) K. Fluid Phase Equilib. 2011, 303, 120−125. (26) Popovych, O.; Tomkins, R. P. T. Nonaqueous Solution Chemistry; John Wiley & Sons, Inc.: New York, 1981.
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dx.doi.org/10.1021/je300017m | J. Chem. Eng. Data 2012, 57, 1939−1944
