Preparation of heterogeneous interfacial catalyst benzimidazole-based acid ILs@MIL-100(Fe) and its application in esterification

A functionalized heterogeneous interfacial catalyst (BIMAILs@MIL-100(Fe)) is fabricated by encapsulating benzimidazole-based acidic ionic liquids (ILs:[BIMAILs]HSO₄) into the cages of MIL-100(Fe) framework. The characterization of the target heterogeneous catalyst is represented by SEM, FT-IR, XRD, N₂ adsorption-desorption and EA techniques, and its catalytic activity is assessed by the esterification on the interface between heterogeneous catalyst and oleic acid/methanol. The effect of esterification temperature, esterification time, molar ratio of methanol/oleic acid, and catalyst dosage is elaborated to obtain its optical reaction condition, respectively. The results show that [BIMAILs]HSO₄ ILs are effectively encapsulated in the cages of MIL-100(Fe) framework, and the prepared heterogeneous interfacial catalyst displays the excellent catalytic activity by the esterification of oleic acid, resulting in a maximum conversion of oleic acid 92.3% under the optimized situation, and the conversion is only reduced from 92.3–84.1% when the catalyst is reused for 6 cycles, which indicates that the prepared heterogeneous catalyst has good reusability.