Ionic liquid bmimCl/formamide mixture as the polar phase of nonaqueous microemulsions

The solution of ionic liquid (IL) bmimCl and polar organic solvent formamide (FA) were used to form nonaqueous microemulsions in cyclohexane by the aid of surfactant Triton X-100 (TX-100). The phase behavior of the bmimCl–FA/TX-100/cyclohexane system at 25 ± 0.1 °C was studied. Electrical conductivity measurement was used to identify the microstructures of the nonaqueous microemulsions. Based on the phase diagram, the reverse microemulsions containing bmimCl–FA as the internal phase were investigated by the dynamic light scattering (DLS) and UV–vis spectroscopy. The result of DLS experiments confirmed the formation of reverse microemulsions of bmimCl–FA in cyclohexane. The UV–vis studies with methyl orange (MO) and methylene blue (MB) as absorption probes further confirmed the existence of reverse microemulsions. UV–vis studies using CoCl2 as probe also indicated that the reverse microemulsions could dissolve metal salt.

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► Microemulsions with ionic liquid and a nonaqueous polar solvent as the polar phase.
► Characterization by means of conductivity, DLS and UV–vis spectroscopy.
► Linear increase of the microemulsions droplet size by adding the polar phase.
► These nonaqueous microemulsions can dissolve metal salt.