Journal of Chemical and Engineering Data, Vol. 49, No. 6, 2004 1551
Table 1. Measured Vapor Pressures of the X[bmim][Br]
+
Water System
X ) 20 mol % X ) 40 mol % X ) 60 mol % X ) 80 mol %
T/K
P/kPa
T/K
P/kPa
T/K
P/kPa
T/K
P/kPa
3
04.8
20.6
26.8
33.4
38.4
43.4
46.6
51.6
56.6
61.0
65.8
68.6
75.4
79.4
83.2
3.5 320.6
7.9 332.8
10.8 341.0
14.0 353.8
17.7 359.5
21.1 365.0
24.3 370.8
29.5 375.6
36.4 380.2
43.2 384.6
51.9 387.4
58.1 392.2
72.9 395.8
82.6 400.8
4.1 355.6
7.2 361.0
10.4 369.2
16.5 376.0
21.4 381.6
25.8 386.8
31.2 395.0
37.4 400.6
43.6 406.8
49.3 411.8
56.6 416.2
64.5 420.2
71.5 425.2
8.8 379.4
11.2 387.4
15.3 392.0
19.2 396.8
24.1 402.4
29.4 407.6
36.4 413.0
42.5 418.5
50.6 422.6
58.4 426.4
68.2 430.8
75.7 434.2
87.6 437.4
11.3
14.5
17.4
19.9
24.1
27.5
32.4
37.3
41.3
47.5
51.8
58.1
62.9
70.1
77.3
83.7
91.9
96.5
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
84.1 431.2 103.0 441.6
95.8 407.2 103.1
446.4
450.8
85.4 103.2
4
4
4
53.6
56.2
57.4 101.2
Figure 1. Experimental apparatus for vapor-pressure measure-
ments: 1, sample vessel; 2, condenser; 3, mercury manometer; 4,
thermocouple; 5, bath; 6, vacuum pump; 7, 8, stirrer; 9, circulator;
Table 2. Measured Vapor Pressures of the X[bmim][BF4]
+ Water System
1
0, needle valve; 11, trap.
X ) 20 mol % X ) 40 mol % X ) 60 mol % X ) 80 mol %
of water present. The product was recrystallized from dry
acetonitrile and dried under vacuum at 70 °C for 12 h to
T/K
P/kPa
T/K
P/kPa
T/K
P/kPa
T/K
P/kPa
yield pure crystalline [bmim][[Cl]. A solution of [bmim][Cl]
311.4
318.0
3.9 320.4
6.1 332.0
10.5 341.6
16.0 351.4
22.3 360.4
29.7 369.4
40.6 377.0
53.3 385.2
66.9 389.8
82.4 395.0
3.5
6.5
342.0
353.2
359.8
367.4
374.2
380.6
389.0
396.0
403.6
409.2
414.6
3.9 375.0
7.2 385.0
10.0 401.0
13.7 413.0
17.6 424.2
22.2 431.4
29.4 435.4
37.3 442.6
45.8 448.4
55.0 451.8
63.0 457.6
74.6 464.8
4.3
6.8
3
(
93 g, 0.531mol) in acetone (500 cm ) at room temperature
3
3
3
3
27.8
35.8
44.0
50.8
10.2
15.9
22.6
32.1
41.8
56.0
68.2
82.1
92.0
12.2
17.8
24.1
29.6
35.5
43.1
51.8
59.0
68.9
80.7
was added to sodium tetrafluoroborate (58.3 g, 0.531 mol).
After 24 h of stirring, the resulting NaCl precipitate was
then filtered through a plug of Celite, and the volatiles were
removed by rotary evaporation to leave a yellowish, clear
liquid. The product was dried for 3 more days under a high
358.0
64.4
368.4
3
1
vacuum of 0.03 mmHg. The chemical shifts for the H NMR
3
3
76.4
spectrum (ppm, D
2
O) appear as follows: δ 8.71[s, 1H, H(2)],
.49[s, 1H, H(4)], 7.44[s, 1H, H(5)], 4.21[t, 2H, NCH ],
.91[s, 3H, NCH ], 1.87[m, 2H, NCH CH ], 1.35[m, 2H,
CH CH ] and 0.94[t, 3H, CH ]. Water and chloride
contents were 100 ppm and 1.10%, respectively.
bmim][Br]. In a three-necked, 1000-mL round-bot-
80.6 102.6 398.4
7
3
2
4
19.4
425.0
430.8 102.2
3
2
2
86.6 475.2 101.6
NCH
2
2
2
3
[
dried for 5 more days under high vacuum at (70 to 80) °C.
1
tomed flask equipped with a reflux condenser, dropping
funnel, and magnetic stirrer, under vigorous stirring,
The chemical shifts for H NMR spectrum (ppm, DMSO -
6
d ) appear as follows: δ 9.05[s, 1H, H(2)], 7.70[s, 1H, H(4)],
3
05.64 g (390 mL, 2.85 mol) of freshly distilled bromo-
7.67[s, 1H, H(5)], 5.14[t, 1H, OH], 4.20[m, 2H, NCH
2 2
CH ],
butane was added dropwise over 1 h to a solution 225.43
mL (232.2 g, 2.83 mol) of 1-methylimidazole in 200 mL of
3.86 [s, 3H, NCH ], 3.72 [t, 2H, NCH ]. Water and chloride
3
2
contents were 160 ppm and 1.51%, respectively.
1
,1,1-trichloroethane at ambient temperature. The mixture
Apparatus and Procedure. The vapor pressures were
measured by the boiling-point method. The apparatus for
the vapor-pressure measurement primarily consisted of an
was then heated under reflux for 2 h and decanted from
the hot solution in a separatory funnel, washed twice with
3
00 mL of trichloroethane at 50 °C, and then dried under
3
equilibrium vessel with an internal volume of 100 cm , a
1
reduced pressure at 40 °C for 3 days. The H NMR
constant-temperature bath, a condenser, a U-tube mercury
manometer capable of reading to 0.5 mm, a K-type thermo-
couple with an accuracy of (0.1 K, and two stirrers. The
K-type thermocouple with the digital thermometer was
calibrated with a standard thermometer. The schematic
diagram is shown in Figure 1. A sample solution of a
desired IL concentration was prepared. The sample solu-
spectrum (ppm, D
2
O) contains the following peaks: δ 8.91[s,
H, H(2)], 7.64[s, 1H, H(4)], 7.59[s, 1H, H(5)], 4.32[t, 2H,
1
NCH
2
], 4.02 [s, 3H, NCH
CH CH ], 1.00 [t, 3H, CH
content was 200 ppm.
hydemim][BF ]. A 1000-mL three-necked round-bot-
3
2 2
], 1.95 [m, 2H, NCH CH ], 1.42
[
m, 2H, NCH
2
2
2
3
]. The water
[
4
3
tom flask fitted with a water condenser and a gas inlet and
provided with a Teflon-coated magnetic spin bar was
tion with an approximate volume of 70 cm was placed in
the vessel and evacuated to the proper pressure. The
sample solution was then heated and stirred well with a
magnetic stirrer to prevent superheating. At thermal
equilibrium, the pressure in the apparatus and the tem-
perature of the sample solution were measured. A sample
solution of a desired absorbent concentration was used in
each run. The condenser was worked with a sufficiently
cooled temperature (≈ -10°C) to minimize the amount of
condensed vapor because this water vapor can vary the
initial concentration.7
charged under N
-Chloroethanol (200 mL) was added to the reaction vessel.
The reaction mixture was heated under N at 80 °C for
20 h. Recrystallization from acetonitrile on cooling was
performed repeatedly to give [hydemim][Cl]. [hydemim][Cl]
162 g, 1 mol) in dichloromethane at room temperature was
2
with 1-methylimidazole (246.3 g, 3 mol).
2
2
1
(
added to sodium tetrafluoroborate (110 g, 1mol). After 24
h of stirring, the resulting NaCl precipitate was then
filtered through a plug of Celite. The resulting liquid was
,11-14