Immobilization of Ionic Liquids in Layered Compounds via Mechanochemical Intercalation

A facile mechanochemical intercalation approach was adopted to immobilize 1-butyl-3-methylimidazolium chloride (BMIMCl) in layered α-zirconium phosphate (ZrP). The intercalation compounds with an expanded layer distance were confirmed by X-ray diffraction. Thermogravimetric characterization revealed that a portion of the BMIMCl was intercalated into the ZrP galleries, while a portion was adsorbed on the layer surface. The immobilized BMIMCl was evaluated for catalysis evaluation of the coupling reaction of CO₂ and propylene oxide to synthesize propylene carbonate. The immobilized BMIMCl exhibited similar reactivity as free BMIMCl. Overall, the mechanochemical approach proves to be effective in immobilizing ionic liquids in layered compounds and thus may expand the applications of ionic liquids and, meanwhile, improve catalyst separation and recycling.