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Supporting Information
A quick and green approach to prepare [Rmim]OH and its application in
hydrophilic ionic liquid synthesis
Jian Gao, Jianguo Liu, * Wenming Liu, Yun xie, Yuchen Xin, Ying Yin, Bo li, Xiao Jie, Jun Gu, Zhigang
Zou**
†
Eco-materials and Renewable Energy Research Center, Department of Materials Science and Engineering, Department of Physics and National Laboratory of
Solid State Microstructures, Nanjing University, 22# Hankou Road, Nanjing, Jiangsu province, China.P.R.C
Table of contents
1
1. H NMR spectrum ....................................................................................................................................................................... 1
2. Elemental analysis ...................................................................................................................................................................... 4
3 Potassium concentration .............................................................................................................................................................. 4
4. Br content calculation when KOH:[Rmim]+Br- is one ............................................................................................................... 4
5 Solubility measurement ............................................................................................................................................................... 5
1.1H NMR spectrum
N
N
δH (500 MHz, D2O) 8.60 (s, 1H; imidazole H), 7.38 (s, 1H; imidazole H) , 7.31 (s, 1H; imidazole H) , 4.14-4.10 (m, 2H;CH2) ,3.79 (s,
3H;CH3) ,1.39 (t,3J(H-H)=7.5Hz;3H;CH3)
Figure 1 1H NMR for [Emim]+HSO4-
Electronic Supplementary Material (ESI) for New Journal of Chemistry
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N
N
δH (500 MHz, D2O) δ=8.60 (s, 1H; imidazole H), 7.37 (s, 1H; imidazole H) , 7.31 (s, 1H; imidazole H) , 4.13-4.10 (m, 2H;CH2) ,3.78 (s,
3H;CH3) ,1.38 (t,3J(H-H)=7.5Hz;3H;CH3)
Figure 2 1H NMR for [Emim]+H2PO4-
N
N
δH (500 MHz, D2O) δ=8.66 (s, 1H; imidazole H), 7.45 (s, 1H; imidazole H) , 7.39 (s, 1H; imidazole H) , 4.21-4.19 (d, 2J(H-H)=10Hz;
2H;CH2) ,3.86 (s, 3H;CH3) ,1.47 (t,3J(H-H)=7.25Hz;3H;CH3)
Figure 3 1H NMR for [Emim]+BF4-
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N
N
δH (500 MHz, D2O) δ=8.63 (s, 1H; imidazole H), 7.39 (s, 1H; imidazole H) , 7.35 (s, 1H; imidazole H) , 4.12
(t,3J(H-H)=7.5Hz;2H;CH2) ,3.81 (s, 3H;CH3) , 1.74-1.80 (m,2H;CH2), 1.26-1.21 (m, 2H; CH2), 0.84 (t,3J(H-H)=7.5Hz; 3H; CH3)
Figure 4 1H NMR for [Bmim]+H2PO4-
N
N
δH (500 MHz, D2O) δ=8.66 (s, 1H; imidazole H), 7.45 (d, ,2J(H-H)=1.5Hz;1H; imidazole H) , 7.40 (s, 1H; imidazole H) , 4.18-1.86 (m,
2H;CH2 ,3.87 (d, 2J(H-H)=2.5Hz;3H;CH3) , 1.83-1.82 (m,2H;CH2), 1.30 (t,3J(H-H)=7Hz; 2H; CH2) , 0.91-0.88 (m,3H;CH2)
Figure 5 1H NMR for [Bmim]+BF4-
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2. Elemental analysis
Table-1 Elemental analysis
1
[Emim]+HSO4calc
found
C[%] 34.61
34.55
H[%] 5.77
6.04
N[%] 13.46
13.42
2
[Emim]+H2PO4calc
found
34.61
34.57
6.25
6.18
13.46
13.17
3
[Emim]+BF4calc
found
36.44
36.53
5.56
5.69
14.15
13.91
4
[Bmim]+BF4calc
found
42.66
42.72
6.66
6.72
12.44
12.30
5
[Bmim]+H2PO4calc
found
40.67
40.57
7.20
7.23
11.86
10.46
3 Potassium concentration
Potassium was introduced into the system with KOH. Thus it is necessary to check how much
potassium remains in the final product. Most the potassium can be removed with the precipitation of
potassium salts as the solubility of most the potassium salts in ethanol are very low in ethanol.
Therefore, the K content should be very low in the final product. To check the content, atomic
absorption spectroscopy (AAS) method was applied as the follows: a certain amount of the obtained
sample was dissolved in the water in a comparison tube (10 mL). The potassium content was then
measured on Atomic Absorption Spectrometer (Varian AA240FS). The final content of the sample
was then calculated according to the sample concentration and the value measured from the
instrument. The results are presented in Table 2. The K concentration measured is that for the sample
solution.The final K content for the sample (CK, in ppm) was calculated with equation (S1).
Ck=1,000,000*((10*C/1000)/1000)/m
(S1)
Where C is the concentration of potassium for the sample solution measured directly with AAS
in mg.L-1 and m is the weight of the samples in mg. It can be seen that the K content values were
found to be at 100 ppm grade. This value is relatively low and should be in the acceptable range.
Table 3 Potassium concentration of sample
Sample
C
1 [Emim]HSO4 1.342
2 [Bmim]DHP 1.837
3 [Emim]DHP 1.826
4 [Emim]BF4
5 [Bmim]BF4
1.546
1.947
m
0.226
0.178
0.180
0.174
0.165
K(wt%)
CK
5.94×10
-5
59.38
1.03×10
-4
103.20
1.03×10
-4
101.44
8.89×10
-5
88.85
1.18×10
-4
118.00
4. Br content calculation when KOH:[Rmim]+Br- is one
+
-
The Br content is calculated with equation (S2) when KOH:[Rmim] Br =1
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Br.wt % = 789 L *
Where
789
L
s
MX
MKX
s
M
1
* X * * 100%
100 M KX m
2)
(S
is the density of ethanol(g/L),
is the volume of ethanol used(litter),
is the solubility of KX in ethanol(g /100g
ethanol),
is the atomic weight of X,
is the molecular weight of KX,
5 Solubility measurement
We failed to find the solubility of KOH in propanol and iso-propanol and the data were obtained
experimentally. The detailed procedure is as the follows: a 10g KOH was added to 25 mL propanol and
iso-propanol. The mixtures were stirred for two hours to prepare saturated KOH solution. Then a drop of
the saturated KOH solution was taken and dropped on a slide which had been weight to be ms, the slide
together with the solution was weight to be M. The solution together with the slide was then dried for 4
hours to vaporize or the solvent. The slide and the dry KOH was weight to be m0 Thus the solvent weight
is M-m0, while the KOH weight is m0-m The solubility (S) was then determined as (S3). For each solvent,
two data was measured and the average value was taken.
S=
m0 − m
× 100
M − m0
(S3)
6 Two-step method to prepare [Bmim]BF4
The reaction was much the same as described in 1-3 and summarize here as the following:
0.1mol [Bmim]X and 0.12mol NaBF4 were added to a 250 ml three-necked flask. Then 60ml
propanol was added and the system as stirred for 24 hours. The insoluble NH4Cl metathesis product was
removed by filtration in air. The final colorless and odorless [Bmim]BF4 was subsequently dried under
vacuum at 120°C for 24 hours. The obtained samples were then submitted for Cl and Br content
measurement as described in the main text.
Reaction between the [Emim]Br and NaHSO4 and NH4H2PO4 was also carried out as described
above.
Electronic Supplementary Material (ESI) for New Journal of Chemistry
This journal is © The Royal Society of Chemistry and The Centre National de la Recherche Scientifique 2011
Reference
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