Catalytic activity and stability of sulfonic-functionalized UiO-66 and MIL-101 materials in friedel-crafts acylation reaction

Sulfonic-containing UiO-66 and MIL-101 MOF materials, prepared by direct synthesis with a sulfonic acid-including benzene dicarboxylate (SO3H-BDC) linker, have been evaluated as acid catalysts in Friedel–Crafts acylation of anisole with acetic anhydride. The catalytic activity of these materials was compared to other conventional acidic sulfonic heterogeneous catalysts, such as commercial Nafion-SAC-13 and Amberlyst-15. The catalytic performance of MOF materials was significantly dependent on their textural properties and the availability of sulphonic acid groups. MIL-101-SO3H material displayed a remarkable anisole conversion and specific activity per sulfonic acid centre due to its open structure and multimodal pore size distribution. The inherent properties of MIL-101-SO3H material allowed a more sustainable catalyst regeneration than those used for conventional heterogeneous catalysts due to the deposition of reagents and products, in particular poly-acetylated compounds. MIL-101-SO3H proved an easy recovery and reusability in successive runs without any loss of activity. These promising results evidenced the potential of MIL-101-SO3H as an alternative catalyst for acid-catalyzed reactions.