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sulfonimide (LiNTf , Aldrich 99%) were used as received. (4-Cyano-
obtained was 19.92 g (61.5 mmol, 46.2%) and the purity was veri-
fied by using H NMR spectroscopy.
2
1
pentanoic acid)-4-dithiobenzoate (CPA) was synthesised by follow-
[39,40]
ing the literature procedure.
2
-(1-Butylimidazolium-3-yl)ethyl methacrylate bromide ([BIEMA]
The ionic liquids 1-butyl-3-methylimidazolium tetrafluoroborate
[Br]): 2-Bromoethyl methacrylate (24.91 g, 128 mmol) and a small
amount of 2,6-di-tert-butyl-p-cresol were mixed followed by the
dropwise addition of butyl imidazole (19 mL, 145 mmol). The mix-
ture was allowed to react at 408C overnight. In the next step, the
mixture was dissolved in water (300 mL) and washed twice with
ethyl acetate and once with chloroform. The water was evaporat-
ed, and the residue was dissolved in acetonitrile. The acetonitrile
solution was filtered through a plug of silica and a 0.45 mm PTFE
membrane. The solvent was evaporated and the product dried
under vacuum. The synthesis yielded 21.32 g (67.2 mmol, 53%) of
the product.
[
C mim][BF ] and 1-butyl-3-methylimidazolium hexafluorophos-
4 4
phate [C mim][PF ] were synthesised by M. V. Lomonosov at
4
6
Moscow State University (Russia) and characterised by using
1
H NMR spectroscopy.
1
[
C mim][BF ]: H NMR (300 MHz, [D ]DMSO): d=0.89 (3H, t,
4
4
6
NHCH CH CH CH ), 1.26 (2H, m, NCH CH CH CH ), 1.76 (2H, p,
2
2
2
3
2
2
2
3
NCH CH CH CH ), 3.84 (3H, s, NCH ), 4.15 (2H, t, NCH CH CH CH ),
2
2
2
3
3
2
2
2
3
7
.72 (2H, m, C(5)H, C(4)H), 9.08 ppm (1H, s, C(2)H).
1
[
C mim][PF ]: H NMR (300 MHz, [D ]DMSO): d=0.91 (3H, t,
4 6 6
NHCH CH CH CH ), 1.27 (2H, m, NCH CH CH CH ), 1.77 (2H, p,
2
2
2
3
2
2
2
3
NCH CH CH CH ), 3.85 (3H, s, NCH ), 4.16 (2H, t, NCH CH CH CH ),
2
2
2
3
3
2
2
2
3
Poly[2-(1-butylimidazolium-3-yl)ethyl methacrylate tetrafluorobo-
rate] (P1 [BIEMA][BF ]): [BIEMA][BF ] (10.92 g, 33.7 mmol), CPA
7
.72 (2H, m, C(5)H, C(4)H), 9.09 ppm (1H, s, C(2)H).
4
4
All the solutions were prepared by weighing (Mettler Toledo
(1.82 mg, 6.51 mmol) and ACPA (56.2 mg, 2.01 mmol) were dis-
solved in acetonitrile (55 mL). The solution was subjected to five
ꢀ4
AB204-S/PH) the amounts needed with a precision of ꢁ1ꢃ10 g.
CO (99.99%), Ar (99.999%) and N (99.999%) were obtained from
freeze–thaw cycles and filled with N . The solution was heated to
2
2
2
AGA Oyj (Finland).
758C and allowed to react for 7 h. The reaction was quenched by
freezing the solution with liquid nitrogen and exposing it to the at-
mosphere. At this point, a sample was withdrawn to determine the
conversion of the reaction by using NMR spectroscopy. The conver-
sion was found to be 82.4%. The polymer was isolated by precipi-
tation with ethyl acetate. The polymer was further purified by two
consecutive precipitations from acetone by ethyl acetate, at which
point no residual monomer could be observed in the NMR spec-
trum. The polymer was then dissolved in acetonitrile and freeze
Syntheses
The monomers were synthesised by using a method adapted from
[29]
the literature with some modifications. Representative syntheses
are reported here, and other batches were synthesised similarly.
The polymerisations were conducted by using RAFT polymeri-
[30,31]
1
sation.
dried. The purity of the product was verified by H NMR spectros-
copy.
2
-Bromoethyl methacrylate: A flask was charged with 2-bromoe-
thanol (30.1403 g, 241 mmol), dry methylene chloride (200 mL) and
triethylamine (45 mL, 323 mmol). After cooling the flask in an ice
bath for 1 h, methacrylic acid chloride (27 mL, 276 mmol) in dry
methylene chloride (50 mL) was added slowly with vigorous stir-
ring. The flask was stirred in the ice bath for 45 min. The flask was
then warmed to RT, and the mixture was allowed to react over-
night. The solution was filtered to remove the salt formed as a side
product. The filtrate was then washed twice with saturated aque-
ous sodium carbonate and twice with distilled water, followed by
drying over anhydrous sodium sulfate. Methylene chloride was
then evaporated and a small amount of 2,6-di-tert-butyl-p-cresol
was added to inhibit the polymerisation. The product was then pu-
rified by distillation under reduced pressure. The yield obtained
was 26.3687 g (135 mmol, 56%).
Poly[2-(1-butylimidazolium-3-yl)ethyl methacrylate bromide] (P5
[BIEMA][Br]):
A flask was charged with [BIEMA][Br] (16.53 g,
52.1 mmol), CPA (291.2 mg, 1.04 mmol), ACPA (47.9 mg,
0.171 mmol) and methanol (66 mL). The flask was subjected to five
freeze–thaw cycles, filled with nitrogen and allowed to react at
708C for 22 h. The reaction was quenched by immersing the flask
in liquid nitrogen and exposing the reaction mixture to the atmos-
phere. The conversion was determined to be 45.6% by using NMR
spectroscopy. The product was purified by three precipitations
from methanol by an acetone/hexane mixture. The polymer was
then dissolved in water and freeze dried.
Ion exchange of B-24: One of the ion exchange procedures (P5
ꢀ
ꢀ
ꢀ
[
BIEMA][PF ]) is presented; the OTf , NTf and BF4 versions were
6
2
conducted in a similar fashion.
2
-(1-Butylimidazolium-3-yl)ethyl methacrylate tetrafluoroborate
P5 [BIEMA][Br] (1.02 g, which corresponds to 3.18 mmol of repeat-
ing units) was dissolved in water (15 mL). The polymer solution
was added to a solution of NH PF (5.19 g, 31.8 mmol) in water in
(
[BIEMA][BF ]): 2-Bromoethyl methacrylate (25.94 g, 133 mmol) was
4
mixed with butyl imidazole (20 mL, 152 mmol) and a small amount
of 2,6-di-tert-butyl-p-cresol. The mixture was heated to 408C and
allowed to react for 46 h. The reaction mixture was diluted with
water (300 mL) and washed three times with ethyl acetate
4
6
a centrifuge tube with stirring. The polymer immediately precipi-
tated, but the mixture was allowed to stir for approximately 1 h.
In the next step, the polymer was isolated by centrifugation and
washed extensively with water. The polymer was then dissolved in
a mixture of acetone (20 mL) and DMF (2 mL) and precipitated
with NH PF (1.42 g, 8.71 mmol) in water (50 mL), centrifuged and
(
300 mL) and subjected to vacuum to remove dissolved ethyl ace-
tate. To the aqueous phase was added NaBF (16.42 g, 150 mmol)
4
in water (100 mL), and the immediate formation of a viscous layer
at the bottom of the flask was observed. To reduce the viscosity of
the formed ionic liquid, methylene chloride (120 mL) was added
and the phases were separated. The aqueous phase was further ex-
tracted with methylene chloride (50 mL), which was then com-
bined with the original organic phase. The combined organic
phases were washed twice with water and dried over 3 ꢂ molecu-
lar sieves. The solution was passed through a plug of silica and fil-
tered through a 0.45 mm Teflon membrane. The solvent was evapo-
rated, and the product was further dried under vacuum. The yield
4
6
washed with water again. The polymer was dissolved in acetone
10 mL) and precipitated with pure water with centrifugation and
(
washing. Finally, the polymer was dissolved in acetone, precipitat-
ed with diethyl ether, collected by filtration and dried under
vacuum overnight. The yield was 1.10 g (89.6%).
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2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemSusChem 0000, 00, 1 – 11
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These are not the final page numbers!
Privalova, Elena I.
