Table 1 Abbreviations and chemical structures of the investigated ILs

[Emim]BF₄

1-ethyl-3-methylimidazolium tetrafluoroborate

 + 

[Bmim]BF₄

1-butyl-3-methylimidazolium tetrafluoroborate

 + 

[Hmim]BF₄

1-hexyl-3-methylimidazolium tetrafluoroborate

 + 

[E_OHmim]BF₄

1-thoxy-3-methylimidazolium tetrafluoroborate

−

[Emim]OTF

1-ethyl-3-methylimidazolium trifluoromethanesulfonate

 + 

[Bmim]OTF

1-butyl-3-methylimidazolium trifluoromethanesulfonate

 + 

[Bmim]Cl

1-butyl-3-methylimidazolium chloride

−

[Bmim]Br

1-butyl-3-methylimidazolium bromide

−

[Hmim]Br

1-hexyl-3-methylimidazolium bromide

−