Metal-organic framework MIL-53(Al) was synthesized by a solvothermal method using aluminum nitrate as the aluminium source and 1,4-benzenedicarboxylic acid (H 2 BDC) as the organic ligand. The structure of samples was characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The catalytic activity and recyclability of MIL-53(Al) catalyst for the Friedel-Crafts acylation reaction of indole with benzoyl chloride were evaluated. The reaction conditions were optimized and a reaction mechanism was suggested. The results showed that the MIL-53(Al) catalyst exhibited good catalytic activity and recyclability for the Friedel-Crafts acylation reaction. When the molar ratio of indole and MIL-53(Al) catalyst was 1:0.06 (n 1 :n catalyst ), the molar ratio of indole and benzoyl chloride was 1:3, and the solvent was dichloromethane, the conversion of indole could reach 97.1% and the selectivity of 3-acylindole could reach 81.1% at 25 °C after 8 h. The catalyst can be reused without significant degradation in catalytic activity. After the catalyst was reused five times, the conversion of indole was 87.6% and the selectivity of 3-acylindole was 79.5%.
Novel magnetic Cu-BTC@SiO 2 @Fe 3 O 4 catalysts were synthesized by encapsulating magnetic SiO 2 @Fe 3 O 4 nanoparticles into Cu-BTC through an in situ method. The structure of the catalysts was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, a vibration sample magnetometer (VSM), N 2 adsorption/desorption, and NH 3 -temperature programed desorption (NH 3 -TPD). The catalytic activity and recovery properties of the catalysts for the Pechmann reaction of 1-naphthol (NP) with ethyl acetoacetate (EAA) were evaluated. The results showed that the magnetic Cu-BTC@SiO 2 @Fe 3 O 4 catalysts had the larger surface areas, suitable superparamagnetism, and good catalytic activity for Pechmann reaction. The conversion of 1-naphthol can reach ∼96%, and the selectivity of the production can reach ∼98% over 50.8% Cu-BTC@SiO 2 @Fe 3 O 4 (MCC-10) catalyst under the reaction conditions of 130 °C and 24 h. After the reaction, the catalyst can be easily separated from the reaction mixture by an external magnet. The recovery catalyst can be reused for five times, and the conversion of 1-naphthol can be kept over 90%.
The title catalyst is prepared by addition of aqueous 2-methyl imidazole solution containing NEt 3 to an aqueous suspension of Zn(NO3)2 and SiO2@Fe3O4. The SiO2@Fe3O4 support is obtained from a mixture of NaOAc, polyvinylpyrrolidone, FeCl 3, and ethylene glycol (autoclave, 200 C, 12 h) followed by dispersion of the obtained magnetic particles in a mixture of EtOH and aqueous ammonia, and addition of tetraethoxysilane (ultrasonication, 30 min). The catalyst samples are characterized by XRD, SEM, TEM, FTIR spectroscopy, and magnetic measurements. ZIF-8@SiO 2@Fe3O4 samples exhibit superparamagnetism and good catalytic activity for the Knoevenagel reaction. The conversion of p-chlorobenzaldehyde and the selectivity of the production reaches about 98% at 25 C for 4 h. After reaction, the catalyst is easily separated from the reaction mixture by an external magnet, and can be reused five times. -(LI, Q.; JIANG, S.; JI*, S.; AMMAR, M.; ZHANG, Q.; YAN, J.; J. Solid State Chem. 223 (2015) 65-72, http://dx.
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