Metal-organic framework MIL-53(Al): synthesis, catalytic performance for the Friedel-Crafts acylation, and reaction mechanism

Abstract

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%.

Facile Synthesis of Hierarchically Structured MIL-53(Al) With Superior Properties Using An Environmentally-Friendly Ultrasonic Method For Separating Lead Ions From Aqueous Solutions

“…The XRD pattern of the synthesized MIL-53(Al) is presented in Figure 1. These patterns are very similar to the previous one reported in reference 17 . The XRD pattern of the UAS and CS MIL-53(Al) in this study shows the prominent characteristic peaks at 2θ = 9.38 °, 12.58 °, 17.93 °, 23 ° 48, 25.28 °, 27.33 °, which match the peaks reported in the literature 17 , indicating that MIL-53(Al) is well crystallized and synthesized.…”

“…These patterns are very similar to the previous one reported in reference 17 . The XRD pattern of the UAS and CS MIL-53(Al) in this study shows the prominent characteristic peaks at 2θ = 9.38 °, 12.58 °, 17.93 °, 23 ° 48, 25.28 °, 27.33 °, which match the peaks reported in the literature 17 , indicating that MIL-53(Al) is well crystallized and synthesized. Also, the difference in peak intensities is due to higher ultrasonic energy as a driving force, increasing nucleation rate and leading to a considerable amount of cavitation bubbles 18 .…”

Preparation of mixed-matrix membranes from metal organic framework (MIL-53) and poly (vinylidene fluoride) for use in determination of sulfonylurea herbicides in aqueous environments by high performance liquid chromatography

“…As seen from Fig. 4a, the characteristic peaks of MIL-53 were located at 2h = 9.3°, 17.8°, 21.8°, and 27.2°, which were corresponding to (0 0 1), (1 0 3), (0 0 2), and (0 5 1), respectively, and consistent with that reported [42]. The XRD pattern of MIL-53-PVDF MMM (Fig.…”

Synthesis of hydrophobic MIL-53(Al) nanoparticles in low molecular weight alcohols: systematic investigation of solvent effects

“…The possibility to employ post-synthetic modification 18 and using mixtures of metals 19 or ligands 20 in the same framework material further increase the variability of MIL-53. As a result, MIL-53 has been successfully applied in gas separation 21 and storage 22 , heavy metal capture 23 , catalysis 24,25 and controlled drug delivery 26 . Besides the synthetic variability, MIL-53 is particularly notable for the so called breathing effect 11,27 .…”