Insight into the dispersion behavior of 1-butyl-3-methylimiazolium chloride confined in nanoscale pores of carbon materials

It is important to understand the behaviour of ionic liquids (ILs) in nanoscale pores, as application of supported ionic liquid phase (SILP) materials has attracted much attention. The main intention of this investigation is to study the dispersion performance of ionic liquid on activated carbons with different surface oxygen groups. Several active carbons with diverse oxygenated surface groups were obtained by oxidation and reduction methods. All samples were impregnated with [Bmim]Cl at different loadings. The blocked porosity of ionic liquid on SILP materials mainly depends on the amount of ionic liquid and surface oxygen content. In addition, stability of the supported IL in water was tested by analyzing the leached amount of IL. We found that the supported IL is not easily leached from the interface of carbon with low amount of surface oxygen. This may be due to the high free π-electron density of oxygen-free supports, forming more CH–π bonds with H atoms at the C2 position of the acidic cation. In addition, we propose that dispersion of ionic liquid in the pores depends on the density of surface free π-electrons of carbon materials.