2.2.3. Synthesis of ionic liquids
i) Synthesis of 1-(4-sulfonate)-butayl-3-methyl imidazolium zwitterion
1-Methylimidazole and 1,4-butane sultone were mixed in equal molar ratio
in an ice bath. Firstly, 1-methylimidazole was dissolved in acetonitrile
and 1,4-butane sultone was added dropwise to the solution. Then, the
solution was stirred at 40 °C for 24 h in N2 atmosphere,
and the obtained white solid was collected and washed three times with
acetonitrile to remove the unreacted materials. The solid was dried at
60 °C under vacuum for 12 h to form 1-(4-sulfonate)-butayl-3-methyl
imidazolium zwitterion which denoted as IL1,1H NMR (400MHz, MeOD) δ: 1.8 (m, 2H), 2.06 (m, 2H),
2.9 (t, 2H), 3.97 (s, 3H), 4.3 (t, 2H), 4.67 (s, 1H), 7.57 (s, 1H), 7.64
(s, 1H).
13C NMR (101MHz, MeOD) δ: 21.56, 28.65, 35.23, 47.09
– 50.33, 122.34 – 122.38, 123.63 – 123.67, 136.21 – 136.88.