Al-Based MIL-53 Metal Organic Framework (MOF) as the New Catalyst for Friedel-Crafts Alkylation of Benzene

The solvothermal method was used to synthesize MIL-53(Al) and MIL-53(AlLi) at 120 degrees C. Synthesized catalysts were characterized using X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscope, inductively coupled plasma optical emission spectroscopy, thermogravimetric analysis, BrunauerEmmettTeller, and NH3-temperature-programmed desorption. Synthesized MIL-53(Al) and MIL-53(AlLi) were used to perform alkylation of benzene with ethanol in a gas phase laboratory reactor. Activity tests revealed that MIL-53(AlLi) has better performance compared to MIL-53(Al) with 73% conversion of benzene, complete conversion of ethanol, and 75% selectivity for ethylbenzene at 200 degrees C. The main byproduct is identified as toluene, and other byproducts are detected in very small amount. Both of catalysts show good stability after 14 h time on stream at 200 degrees C. The high activity and product selectivity of MIL-53(AlLi) are attributed to proper acidity strength of catalytic sites. Finally, the new MIL-53(AlLi) catalyst is proposed as a more environmentally friendly and economically favorable alternative for commercial zeolites in the benzene alkylation process.