Post-synthetic modification of NH2-MIL88B(Fe) with sulfonic acid groups for acid-catalyzed epoxide ring-opening reaction

Abstract

A new metal–organic framework-based solid acid catalyst was successfully prepared and exploited in the catalytic ring-opening of epoxides. First, NH₂-MIL-88B(Fe) (Fe-MOF) was prepared through the solvothermal reaction of NH₂-BDC and FeCl₃·6H₂O. Then, the prepared MOF was functionalized with 1,3-propane sultone and subsequently treated with H₂SO₄ to form Fe-MOF-SO₃H. The XRD pattern confirmed the stability of the primary MOF after post-modification steps. Moreover, the presence of –SO₃H groups was exactly proved via FT-IR and X-ray photoelectron (XPS) spectroscopies as well as elemental analysis. In addition, a significant reduction in the specific surface area provided another proof to verify the successful post-modification process. Finally, the prepared MOF-SO₃H was employed in the catalytic ring-opening reaction of epoxides. The obtained results revealed the excellent effect of the prepared catalyst on the epoxide ring-opening in a short time. Moreover, the recovered catalyst exhibited good stability in five successive recycling tests with no considerable loss of its activity.