Supporting Information

Phase Behavior of N2O and CO2 in Room-Temperature Ionic Liquids

[bmim][Tf2N], [bmim][BF4], [bmim][N(CN)2], [bmim][Ac], [eam][NO3], and [bmim][SCN]

Mark B. Shiflett,1* Anne Marie S. Niehaus,1 Beth A. Elliott,1 A. Yokozeki2

1DuPont Central Research and Development, Experimental Station,

Wilmington, Delaware 19880, U.S.A.

232 Kingsford Lane, Spencerport, New York14559,U.S.A.

Table S1 Microbalance Components Contributing to Buoyancy Calculationa

Subscript / Item / Mass
(g) / Material / Density (gcm-3) / Temperature
(K)
s / Dry sample / ms / Ionic Liquid / s / Sample T
(Ts)
a / Interacted gas / ma / Gas / a / (Ts)
i1 / Sample container / 0.5986 / Pyrex / 2.23 / (Ts)
i2 / Wire / 0.051 / Tungsten / 21.0 / (Ts)
i3 / Chain / 0.3205 / Gold / 19.3 / 303.15
j1 / Counter-weight / 0.8054 / Stainless Steel / 7.9 / 298.15
j2 / Hook / 0.00582 / Tungsten / 21.0 / 298.15
j3 / Chain / 0.2407 / Gold / 19.3 / 303.15

a See Fig. 2 for additional details

Table S2 Experimental VLE for N2O (1) + [bmim][BF4] (2)a

T (K) / P (MPa) / 100 x1 / T (K) / P (MPa) / 100 x1
298.1 / 0.0262 / 0.4 / 348.1 / 0.0261 / 0.1
298.1 / 0.0514 / 0.7 / 348.1 / 0.0515 / 0.2
298.1 / 0.0767 / 1.0 / 348.1 / 0.0771 / 0.3
298.1 / 0.1027 / 1.3 / 348.2 / 0.1028 / 0.6
298.1 / 0.1279 / 1.6 / 348.2 / 0.1285 / 0.8
298.1 / 0.1547 / 2.0 / 348.2 / 0.1541 / 0.9
298.1 / 0.2567 / 3.1 / 348.0 / 0.2567 / 1.6
298.1 / 0.5126 / 6.0 / 348.0 / 0.5137 / 3.1
298.1 / 0.7701 / 8.8 / 347.9 / 0.7700 / 4.6
298.1 / 1.0268 / 11.5 / 347.7 / 1.0270 / 5.8
298.1 / 1.2832 / 14.0 / 347.7 / 1.2835 / 7.1
298.1 / 1.5407 / 16.4 / 347.7 / 1.5403 / 8.3
298.1 / 1.7976 / 18.7 / 347.7 / 1.7965 / 9.6
298.1 / 2.0527 / 20.8 / 347.6 / 2.0527 / 10.7
323.1 / 0.0258 / 0.2 / - / - / -
323.1 / 0.0517 / 0.4 / - / - / -
323.2 / 0.0768 / 0.5 / - / - / -
323.1 / 0.1025 / 0.7 / - / - / -
323.2 / 0.1291 / 1.0 / - / - / -
323.1 / 0.1544 / 1.2 / - / - / -
323.1 / 0.2562 / 2.1 / - / - / -
323.1 / 0.5121 / 4.1 / - / - / -
323.2 / 0.7703 / 5.9 / - / - / -
323.1 / 1.0275 / 7.8 / - / - / -
323.2 / 1.2836 / 9.6 / - / - / -
323.2 / 1.5403 / 11.2 / - / - / -
323.1 / 1.7964 / 12.8 / - / - / -
323.2 / 2.0532 / 14.4 / - / - / -

a Ref. [13]

Table S3 Experimental VLE for CO2 (1) + [bmim][BF4] (2)a

T (K) / P(MPa) / 100 x1 / T (K) / P (MPa) / 100 x1
282.8 / 0.0102 / 0.2 / 323.3 / 0.0102 / 0.3
283.0 / 0.0502 / 1.3 / 323.2 / 0.0501 / 0.6
283.1 / 0.1001 / 2.6 / 323.2 / 0.1001 / 1.2
283.1 / 0.4001 / 9.6 / 323.2 / 0.3997 / 4.4
283.3 / 0.6996 / 15.9 / 323.2 / 0.6996 / 7.3
283.1 / 0.9997 / 21.6 / 323.2 / 1.0002 / 10.0
283.1 / 1.3002 / 26.5 / 323.2 / 1.2997 / 12.7
283.2 / 1.5001 / 29.5 / 323.2 / 1.5001 / 14.3
283.1 / 2.0002 / 36.4 / 323.2 / 2.0000 / 18.2
298.0 / 0.0097 / 0.2 / 348.2 / 0.0102 / 0.2
298.2 / 0.0500 / 1.0 / 348.2 / 0.0501 / 0.3
298.1 / 0.1001 / 1.9 / 348.1 / 0.1002 / 0.7
298.2 / 0.3996 / 6.9 / 348.1 / 0.4002 / 3.0
298.2 / 0.7002 / 11.5 / 348.2 / 0.6996 / 5.1
298.0 / 0.9997 / 15.8 / 348.0 / 1.0003 / 7.1
298.2 / 1.3002 / 19.7 / 348.2 / 1.3000 / 8.9
298.0 / 1.5001 / 22.1 / 348.2 / 1.5002 / 10.3
298.1 / 2.0002 / 27.7 / 348.1 / 1.9999 / 13.3

a Ref. [18]

Table S4 Experimental VLE for N2O (1) + [bmim][Ac] (2)a

T (K) / P (MPa) / 100 x1 / T (K) / P (MPa) / 100 x1
- / - / - / 323.1 / 0.0253 / 0.1
- / - / - / 323.1 / 0.0505 / 0.3
- / - / - / 323.1 / 0.0754 / 0.4
- / - / - / 323.2 / 0.1004 / 0.6
- / - / - / 323.1 / 0.1254 / 0.7
- / - / - / 323.2 / 0.1504 / 0.9
283.2 / 0.2504 / 2.1 / 323.2 / 0.2501 / 1.5
283.1 / 0.5006 / 4.8 / 323.2 / 0.5003 / 3.1
283.2 / 0.7502 / 7.7 / 323.2 / 0.7502 / 4.5
283.1 / 1.0010 / 10.7 / 323.1 / 1.0009 / 6.0
283.1 / 1.2503 / 13.6 / 323.0 / 1.2503 / 7.5
283.2 / 1.5001 / 15.8 / 323.1 / 1.4996 / 8.8
283.1 / 1.7505 / 18.5 / 323.2 / 1.7496 / 10.2
283.1 / 2.0005 / 20.7 / 323.2 / 2.0005 / 11.7
298.1 / 0.0252 / 0.3 / 348.1 / 0.0257 / 0.0
298.1 / 0.0501 / 0.6 / 348.2 / 0.0501 / 0.2
298.1 / 0.0752 / 0.8 / 348.1 / 0.0754 / 0.3
298.1 / 0.1003 / 1.1 / 348.0 / 0.1003 / 0.4
298.1 / 0.1253 / 1.3 / 348.0 / 0.1253 / 0.5
298.1 / 0.1504 / 1.5 / 348.0 / 0.1504 / 0.7
298.1 / 0.2500 / 2.3 / 348.0 / 0.2505 / 1.1
298.1 / 0.5003 / 4.6 / 347.7 / 0.5005 / 2.5
298.1 / 0.7504 / 6.7 / 347.5 / 0.7505 / 3.4
298.1 / 1.0007 / 8.8 / 347.3 / 1.0000 / 4.7
298.1 / 1.2514 / 10.8 / 347.3 / 1.2500 / 5.8
298.1 / 1.5006 / 12.8 / 347.3 / 1.5002 / 6.8
298.2 / 1.7500 / 14.7 / 347.3 / 1.7496 / 7.7
298.1 / 2.0007 / 16.7 / 347.5 / 1.9999 / 8.5

a Ref. [14]

Table S5 Experimental VLE for CO2 (1) + [bmim][Ac] (2)a

T (K) / P (MPa) / 100 x1 / T (K) / P (MPa) / 100 x1
283.1 / 0.0102 / 19.2 / 323.1 / 0.0104 / 10.8
283.1 / 0.0502 / 27.3 / 323.1 / 0.0504 / 17.6
283.1 / 0.1002 / 30.7 / 323.1 / 0.1004 / 20.4
283.1 / 0.3997 / 35.7 / 323.1 / 0.3995 / 26.3
283.1 / 0.6994 / 39.3 / 323.2 / 0.7003 / 29.2
283.1 / 0.9993 / 41.6b / 323.1 / 1.0001 / 31.5
283.1 / 1.3016 / 44.9b / 323.1 / 1.3002 / 33.4
283.0 / 1.4999 / 46.7b / 323.1 / 1.4995 / 34.6
283.1 / 1.9999 / 51.1b / 323.2 / 1.9993 / 37.3
298.1 / 0.0101 / 18.8 / 348.1 / 0.0104 / 6.3
298.1 / 0.0502 / 25.2 / 348.1 / 0.0505 / 12.9
298.1 / 0.1003 / 27.4 / 348.1 / 0.1000 / 16.1
298.1 / 0.3999 / 32.4 / 348.1 / 0.4002 / 22.6
298.1 / 0.7002 / 35.5 / 348.1 / 0.6994 / 25.3
298.1 / 0.9996 / 38.1 / 348.1 / 1.0003 / 27.2
298.2 / 1.3001 / 40.5 / 348.1 / 1.2994 / 28.7
298.1 / 1.5001 / 42.0 / 348.1 / 1.4997 / 29.4
298.1 / 1.9994 / 45.5 / 348.2 / 1.9993 / 31.6

a Ref. [24]

b Data not included in Ref. [24]

Table S6 Experimental VLE for N2O (1) + [bmim][SCN] (2)

T (K) / P (MPa) / 100 x1
298.7 / 0.0000 / 0.2
298.1 / 0.0101 / 0.2
298.1 / 0.0502 / 0.7
298.1 / 0.1002 / 1.2
298.1 / 0.4004 / 4.0
298.1 / 0.6999 / 6.7
298.1 / 1.0005 / 9.3
298.1 / 1.3008 / 11.9
298.1 / 1.4999 / 14.0
298.1 / 2.0002 / 17.8

Table S7 Experimental VLE for CO2 (1) + [bmim][SCN] (2)

T (K) / P (MPa) / 100 x1
297.1 / 0.0000 / 0.0
298.1 / 0.0113 / 0.1
298.1 / 0.0256 / 0.2
298.1 / 0.0502 / 0.5
298.1 / 0.0751 / 0.7
298.1 / 0.1004 / 0.8
298.1 / 0.1257 / 1.0
298.1 / 0.1509 / 1.2
298.1 / 0.2503 / 1.9
298.1 / 0.5004 / 3.8
298.1 / 0.7503 / 5.6
298.1 / 1.0005 / 7.4
298.1 / 1.2515 / 9.0
298.1 / 1.5003 / 10.7
298.1 / 1.7508 / 12.2
298.2 / 2.0007 / 13.8

1

Table S8 Henry’s law constant (MPa)for N2O using the Conventional Methoda; see text for details

Ionic Liquids

/ 1st order
(without 0) / 1st order
(with 0) / 2nd order
(without 0) / 2nd order
(with 0) / 3rd order
(without 0) / 3rd order
(with 0)
[bmim][Tf2N]
Data points / 4.320.08
15 / 4.300.07
16 / 3.200.03
15 / 3.210.02
16 / 3.350.04
15 / 3.340.04
16
[bmim][BF4]
Data points / 8.560.05
15 / 8.540.05
16 / 7.880.04
15 / 7.860.04
16 / 8.020.09
15 / 7.930.10
16
[bmim][N(CN)2]
Data points / 9.150.04
15 / 9.150.03
16 / 8.660.05
15 / 8.690.05
16 / 8.750.13
15 / 8.820.12
16
[bmim][Ac]
Data points / 10.910.03
15 / 10.900.03
16 / 10.990.11
15 / 10.920.12
16 / 10.580.26
15 / 10.410.25
16
[eam][NO3]
Data points / 28.350.83
15 / 28.370.09
16 / 29.320.17
15 / 29.410.02
16 / 29.260.43
15 / 29.580.45
16
[bmim][SCN]
Data points / 12.990.03
15 / 12.980.03
16 / 12.810.10
15 / 12.780.10
16 / 12.880.26
15 / 12.790.02
16

a Fugacity function fitted with “1st order, (i.e.,linear),” “2nd order,” and “3rd order” polynomials. “Data points” are number of experimental data used in analysis, and/or the theoretical “zero” point (“with 0” or “without 0”). Errors are the standard deviation of the fugacity fitting as a function of N2O mole fractions. N.B.; the standard deviation of each model is generally small, (and unfortunately often such an error is reported in the literature for the uncertainty of the experimental), but the difference in among the fitting models is much larger than the standard deviation.

Table S9 Henry’s law constant (MPa)for CO2 in ionic liquids using the Conventional Methoda; see text for details

Ionic Liquids

/ 1st order
(without 0) / 1st order
(with 0) / 2nd order
(without 0) / 2nd order
(with 0) / 3rd order
(without 0) / 3rd order
(with 0)
[bmim][Tf2N]
Data points / 4.030.62
3 / 3.100.34
4 / 0.722.13
4 / 1.620.31
5 / 3.423.89
7 / 2.560.55
8
[bmim][BF4]
Data points / 6.440.12
9 / 6.400.11
10 / 5.390.02
9 / 5.380.02
10 / 5.410.07
9 / 5.370.06
10
[bmim][N(CN)2]
Data points / 7.530.33
3 / 6.230.53
4 / 5.932.89
4 / 4.060.06
5 / 83.2733.44
5 / 13.667.63
6
[bmim][Ac]b
Data points / -
- / 0.0530.02
2 / -
- / -
- / -
- / -
-
[eam][NO3]
Data points / 19.670.08
11 / 19.690.08
12 / 20.350.22
11 / 20.360.20
12 / 20.510.59
11 / 20.520.50
12
[bmim][SCN]
Data points / 10.200.07
9 / 10.180.06
10 / 10.390.24
9 / 10.280.23
10 / 10.500.67
9 / 10.190.61
10

aFugacity function fitted with “1st order, (i.e. linear),” “2nd order,” and “3rd order” polynomials. “Data points” are number of experimental data used in analysis, and/or the theoretical “zero” point (“with 0” or “without 0”). Errors are the standard deviation of the fugacity fitting as a function of CO2mole fractions. N.B.; the standard deviation of each model is generally small, (and unfortunately often such an error is reported in the literature for the uncertainty of the experimental), but the difference in among the fitting models is much larger than the standard deviation.

b Chemical absorption, limited low-composition data, only 1st order with theoretical “zero” point was calculated.

1

Figure Captions

Fig. S1 Isothermal Px (pressure-liquid composition) phase diagram of N2O (1) + [bmim][Tf2N] (2) binary system, lines: trend lines, symbols: , present VLE data; ▲, VLE data by Anthony et al. [9]

Fig. S2 Isothermal Px (pressure-liquid composition) phase diagram of CO2 (1) + [bmim][Tf2N] (2) binary system, lines predicted by the present EOS calculations, symbols: , VLE data by Anthony et al. [9]

Fig. S3 Isothermal Px (pressure-liquid composition) phase diagram of N2O (1) + [bmim][Tf2N] (2) binary system at 298.15 K, lines: trend lines, symbols: , present VLE absorption data; , present VLE desorption data

Fig. S4 Isothermal Px (pressure-liquid composition) phase diagram of N2O (1) + [bmim][BF4] (2) binary system, lines: trend lines, symbols: , present VLE data at 298.15 K; ▲,VLE data by Revelli et al. [10]

Fig. S5 Isothermal Px (pressure-liquid composition) phase diagram of CO2 (1) + [bmim][N(CN)2] (2) binary system, lines predicted by the present EOS calculations, symbols: , VLE data by Carvalho et al. [30]

Fig. S6 Isothermal Px (pressure-liquid composition) phase diagram of N2O (1) + [bmim][SCN] (2) and CO2 (1) + [bmim][SCN] (2) binary system at 298.15 K, lines: trend lines, symbols: , present N2O VLE data at 298.15 K; ▲,present CO2VLE data at 298.15 K

1