ii) Synthesis of butyl methyl imidazolium bromide
The ionic liquid was prepared following the procedures stated in literature (Huddleston, 2001). 1-Methylimidazole and 1-bromobutane were mixed in a molar ratio of 1:1 in three-necked round bottom flask and refluxed under stirring at 70 ᵒC till two phases (layers) were formed. After removing the unreacted materials the obtained liquid was washed repeatedly with ethyl acetate to remove the unreacted material. Then, the remaining solvent was removed by heating at 70 ᵒC. The pale yellow liquid was distilled under vacuum and the obtained ionic liquid was dried under vacuum at 80 ᵒC and denoted as IL2,Scheme 2. 1H NMR (400MHz, MeOD) δ: 1.0 (t, 3H), 1.41 (m, 2H), 1.91 (m, 2H), 4.02 (s, 3H), 4.31 (t, 2H), 4.68 (s, 1H), 7.64 (d, 1H), 7.7 (d, 1H).