Heteropoly Ionic Liquid Functionalized MOF-Fe: Synthesis, Characterization, and Catalytic Application in Selective Acetalization of Glycerol to Solketal as a Fuel Additive at Room Temperature, Solvent-Free Conditions

In this work, we have reported the synthesis of a series of heterogeneous catalysts, viz., [HMIm]3[PW12O40]@­MOF-Fe, [HMIm]3[PMo12O40]@­MOF-Fe, and [HMIm]4[SiW12O40]@­MOF-Fe, by a simple impregnation method. The catalysts were characterized by several techniques, such as FTIR, EDX, XRD, SEM, elemental mapping, and TGA. Among these materials, [HMIm]3[PW12O40]@­MOF-Fe had more acidic sites (confirmed by potentiometric titration) and high stability around 598 °C (confirmed by TGA). The catalytic prospect of the materials was examined through selective acetalization of glycerol to solketal as a fuel additive under solvent-free and room-temperature conditions. [HMIm]3[PW12O40]@­MOF-Fe exhibited the highest catalytic activity among the three catalysts in terms of glycerol conversion (100%), solketal selectivity (100%), and solketal yield (100%). A recyclability study of [HMIm]3[PW12O40]@­MOF-Fe showed that the material could be reused for up to 7 cycles with insignificant loss in its catalytic performance.