evaporation then dried at 50 °C under vacuum for 24 h. All ILs
prepared by this method were used without purification and pro-
duced in nearly quantitative yields.
Notes and references
1
A. A. Rosatella, S. P. Simeonov, R. F. M. Frade and C. A. M. Afonso,
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-Butyl-3-(3-sulfopropyl)-imidazolium chloride (4). H NMR
(
4
600 MHz, DMSO) δ 9.27 (s, 1H), 7.81 (d, J = 1.3 Hz, 2H),
.29 (t, J = 7.0 Hz, 2H), 4.16 (t, J = 7.2 Hz, 2H), 2.46 (t, J = 7.3
Hz, 2H), 2.13–2.06 (m, 2H), 1.79–1.72 (m, 2H), 1.27–1.19 (m,
3 A. J. Crisci, M. H. Tucker, J. A. Dumesic and S. L. Scott, Top. Catal.,
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2
4
5
6
3
1
3
2
H), 0.87 (t, J = 7.4 Hz, 3H). C NMR (151 MHz, DMSO)
δ 136.31, 122.60, 122.57, 48.67, 47.92, 47.57, 31.38, 26.17,
8.90, 13.39.
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7 A. Harwardt, M. Thomas, F. Geilen, W. Leitner and W. Marquardt,
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-Methyl-3-(3-sulfopropyl)-imidazolium chloride (5). H NMR
(
600 MHz, DMSO) δ 9.17 (s, 1H), 7.78 (s, 1H), 7.71 (s, 1H),
.29 (t, J = 7.0 Hz, 2H), 3.84 (s, 3H), 2.46 (t, J = 7.1 Hz, 2H),
.11–2.05 (m, 2H). C NMR (151 MHz, DMSO) δ 136.87,
8
9
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2
1
13
2
007.
0 M. Mascal and E. B. Nikitin, Angew. Chem., Int. Ed., 2008, 47, 7924–
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1
7
1
-Methyl-3-(3-sulfopropyl)-imidazolium hydrogen sulfate
6). H NMR (600 MHz, DMSO) δ 9.08 (s, 1H), 7.75 (s, 1H),
1
1
(
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1
1
1
2 X. Qi, M. Watanabe, T. M. Aida and R. L. Smith Jr., Green Chem., 2009,
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7
.68 (s, 1H), 4.28 (t, J = 6.5 Hz, 2H), 3.84 (s, 3H), 2.49 (t, J =
.1 Hz, 2H), 2.11–2.06 (m, 2H). C NMR (151 MHz, DMSO)
1
3
δ 136.95, 123.85, 122.49, 47.91, 47.64, 35.95, 26.21.
Recycling studies of 5. In a typical run, the sealed tube was
cooled to room temperature and the hexanes layer was removed
by pipette. 1 mL of de-ionized water was added to the crude
reaction mixture in order to decrease the viscosity of the IL. The
resulting mixture was separated via extraction with ethyl acetate
1
0152–10155.
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1
2
18 B. Girisuta, L. P. B. M. Janssen and H. J. Heeres, Green Chem., 2006, 8,
(8 × 15 mL). After extraction, the remaining 5-water mixture
701–709.
was heated at 80 °C for 2 h under vacuum to remove any
residual ethyl acetate and water. 5 was ready for immediate reuse
in another run under the same conditions previously described.
1
2
9 T. Singh and A. Kumar, J. Phys. Chem. B, 2007, 111, 7843–7851.
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1596 | Green Chem., 2012, 14, 1593–1596
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