Ship‐in‐bottle preparation of multi‐SO3H functionalized ionic liquid@MIL‐100(Fe) for acid‐catalyzed ring‐opening of epoxides

Abstract The fact that the homogeneous acid catalysts are usually separated difficulty than heterogeneous catalysts from the reaction media, the opportunity to combine the advantages of both homogeneous and heterogeneous catalytic systems by immobilizing ILs within the pores of a porous solid support host is an alternative method. In this research, a multi‐SO3H functionalized ionic liquid derived from hexamethylenetetramine (HMTA) and 1,3‐propane sultone was entrapped inside the pores of MIL‐100(Fe) through the ship‐in‐bottle method and utilized for heterogeneous acid‐catalyzed ring‐opening of epoxides under solvent‐free conditions. The physicochemical properties of prepared catalyst were fully elucidated by various methods. FT‐IR spectroscopy and elemental analysis approved the successful incorporation of modified groups within the MIL‐100(Fe) cavities. The concentration of acid sites was measured via the acid–base titration which exhibited the 0.9 mmol/g H+ in the catalyst structure. Also, thermogravimetric analysis (TGA) profile showed the loosing of modified groups at 300–600°C. Moreover, X‐ray diffraction (XRD) analysis showed that the MIL‐100(Fe) structure was retained after modification and nitrogen adsorption–desorption analysis (BET method) manifested the decrease in surface area caused by incorporation of ionic liquid. The fabricated catalyst exhibited high catalytic efficiency in methanolysis of styrene oxide (99% conversion in 3 h) under ambient conditions and used without a substantial drop in product yield in further rounds.