Copper-based MOF-74 material as effective acid catalyst in Friedel–Crafts acylation of anisole

• Cu-MOF-74 is an active catalyst in the Friedel–Craft acylation of anisole.
• Polar solvents diminish the activity of the open metal sites in Cu-MOF-74.
• Cu-MOF-74 phase is stable using low concentration of acylating agent.
• Cu-MOF-74 shows a better catalytic performance than ZSM-5 and Al-MCM-41 materials.

Metal organic frameworks (MOFs) are emerging potential materials for catalytic applications. Among them, the honeycomb M2(dhtp) family, also known as MOF-74 or CPO-27 materials, are characterized by remarkable textural properties and accessible unsaturated metal sites (M). This work has been focused on the catalytic properties of novel Cu-MOF-74 material for the Friedel–Crafts acylation of anisole, as acid-catalyzed reaction test. The influence of reaction variables such as the type of acylating agent and solvent, and the reaction temperature have been studied. Additionally, the stability of Cu-MOF-74 was evaluated under different reaction conditions. Cu-MOF-74 achieved a remarkable catalytic performance in terms of anisole conversion and p-MAP yield. Additionally, the structural MOF-74 phase was preserved when using diluted concentrations of acetyl chloride as acylating agent. The relative acylating agent concentration was demonstrated to be crucial in the collapse of the crystalline MOF-74 phase. The catalytic activity of Cu-MOF-74, in terms of anisole conversion and selectivity to p-MAP product, was also superior to other Cu-containing MOF materials (HKUST-1) and conventional inorganic acid catalysts, such as aluminum-containing microporous zeolites (H-ZSM-5 and BETA) and mesoporous ordered materials (Al-MCM-41). Cu-MOF-74 also showed high stability and remarkable catalytic performance for seven consecutive reaction cycles when this MOF material was used in the best reaction conditions.

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