A mild and efficient method for the synthesis of pyrroles using MIL-53(Al) as a catalyst under solvent-free sonication.
Ontology highlight
ABSTRACT:
SUBMITTER: Nguyen HT
PROVIDER: S-EPMC9062010 | biostudies-literature | 2019 Mar
REPOSITORIES: biostudies-literature
Publications
A mild and efficient method for the synthesis of pyrroles using MIL-53(Al) as a catalyst under solvent-free sonication.
Nguyen Hai Truong HT Nguyen Hai Truong HT Thuy Nguyen Linh Ho LH Le Hoang Doan Tan T Tran Phuong Hoang PH
RSC advances 20190319 16
A highly efficient method for the synthesis of pyrroles using MIL-53(Al) as a catalyst has been developed under solvent-free sonication. This reaction has a broad substrate scope and high yields were obtained within a short reaction time. Remarkably, no additional additives and volatile organic solvent are required for this method and the MIL-53(Al) could be recovered and reused several times without significant drop-off in catalytic activity. ...[more]
Similar Datasets
Project description:Well-dispersed ruthenium nanoparticles (Ru NPs) are immobilized within the pores of amine-functionalized MIL-53 via an in situ impregnation-reduction method. The resulting Ru/MIL-53(Al)-NH2 catalyst exhibits superior catalytic performance for the dehydrogenation of ammonia borane (AB) at ambient temperature relative to the Ru/MIL-53(Al) catalyst; it has a turnover frequency (TOF) of 287 mol H2 min-1 (mol Ru)-1 and an activation energy (E a) of 30.5 kJ mol-1. The amine groups present in the MIL-53(Al)-NH2 framework facilitate the formation and stabilization of ultra-small Ru NPs by preventing their aggregation. Additionally, the Ru/MIL-53(Al)-NH2 catalyst exhibits satisfactory durability and reusability: 72.4% and 86.3% of the initial catalytic activity was maintained after the fifth successive cycle of the hydrolytic dehydrogenation of AB in the two respective tests.
| S-EPMC9079245 | biostudies-literature
Project description:The application of metal-organic frameworks (MOFs) has attracted increasing attention in organic synthesis. The modification of MOFs can efficiently tailor the structure and improve the property for meeting ongoing demand in various applications, such as the alteration of gas adsorption and separation, catalytic activity, stability, and sustainability or reusability. In this study, carboxyethylsilanetriol (CEST) disodium salt was used as a dual-functional ligand for modified Al-MIL-53 to fabricate CEST-functionalized Al-MIL-53 samples through a hydrothermal reaction of aluminum nitrate, terephthalic acid, and CEST disodium salt by varying the molar ratio of CEST to terephthalic acid and keeping a constant molar ratio of Al3+/-COOH of 1:1. The structure, composition, morphology, pore feature, and stability were characterized by XRD, different spectroscopies, electron microscopy, N2 physisorption, and thermogravimetric analysis. With increasing CEST content, CEST-Al-MIL-53 still preserves an Al-MIL-53-like structure, but the microstructure changed compared with pure Al-MIL-53 due to the integration of CEST. Such a CEST-Al-MIL-53 was used as the support to load Pd particles and afford a catalyst Pd/CEST-Al-MIL-53 for Suzuki-Miyaura C-C cross-coupling reaction of aryl halides and phenylboronic acid under basic conditions. The resulting Pd/CEST-Al-MIL-53 showed a high catalytic activity compared with Pd/Al-MIL-53, due to the nanofibrous structure of silicon species-integrated CEST-Al-MIL-53. The nanofiber microstructure undergoes a remarkable transformation into intricate 3D cross-networks during catalytic reaction, which enables the leachable Pd particles to orientally redeposit and inlay into these networks as the monodisperse spheres and thereby effectively preventing Pd particles from aggregation and leaching, therefore demonstrating a high catalytic performance, long-term stability, and enhanced reusability. Obviously, the integration of CEST into MOFs can effectively prevent the leaching of active Pd species and ensure the re-deposition during catalysis. Moreover, catalytic performance strongly depended on catalyst dosage, temperature, time, solvent, and the type of the substituted group on benzene ring. This work further extends the catalytic application of hybrid metal-organic frameworks.
| S-EPMC11820489 | biostudies-literature
Project description:The vast structural and chemical diversity of metal-organic frameworks (MOFs) provides the exciting possibility of material's design with tailored properties for gas separation, storage and catalysis. However, after more than twenty years after first reports introducing MOFs, the discovery and control of their synthesis remains extremely challenging due to the lack of understanding of mechanisms of their nucleation and growth. Progress in deciphering crystallization pathways depends on the possibility to follow conversion of initial reagents to products at the molecular level, which is a particular challenge under solvothermal conditions. The present work introduces a detailed molecular-level mechanism of the formation of MIL-53(Al), unraveled by combining in situ time-resolved high-resolution mass-spectrometry, magic angle spinning nuclear magnetic resonance spectroscopy and X-ray diffraction. In contrast to the general belief, the crystallization of MIL-53 occurs via a solid-solid transformation mechanism, associated with the spontaneous release of monomeric aluminum. The role of DMF hydrolysis products, formate and dimethylamine, is established. Our study emphasizes the complexity of MOF crystallization chemistry, which requires case-by-case investigation using a combination of advanced in situ methods for following the induction period, the nucleation and growth across the time domain.
| S-EPMC9243051 | biostudies-literature
Project description:In this study, hybrids of nanoporous MIL-101(Cr) and MIL-53(Al) were synthesized using a hydrothermal method for various time periods, ranging from 8 to 40 h. The prepared materials were characterized by powder X-ray diffraction (PXRD) and elemental analysis, and their specific surface areas were measured by N2 sorption at 77 K using the Brunauer-Emmett-Teller (BET) method. To investigate the practical application of these materials, the pure carbon dioxide and methane adsorption capacities of the samples were determined using the volumetric method. The Langmuir model was used to fit the CO2 and CH4 isotherms. Extended Langmuir (EL) equations and the ideal adsorbed solution theory (IAST) models were used to obtain the CO2/CH4 selectivity. The sample with the highest BET specific surface area was selected as a candidate for further investigations. The thermal stability of the selected sample was investigated by thermogravimetric analysis (TGA). Scanning electron microscopy (SEM) was used to characterize the sample morphology. XRD results showed that the sample synthesized over the shortest time corresponded to MIL-101(Cr), while the sample synthesized over the longest time was in agreement with MIL-53(Al). Samples synthesized for time periods between these two limits were assumed to be composites of both MIL-53(Al) and MIL-101(Cr). TGA results indicated that the hybrid materials were thermally stable at temperatures about 100 °C higher than for pure MIL-101(Cr). The BET specific surface area (1746 m2 g-1) and CO2 adsorption capacity (16 mmol g-1) of the selected hybrid sample were about 50% and 35% higher, respectively, compared with those of pure MIL-53(Al), but 30% and 20% lower, respectively, compared with those of pure MIL-101(Cr). Binary adsorption modeling showed the high selectivity of the MIL-101(Cr) and MIL-53(Al) hybrid material for CO2 with a minimum separation factor of about 60 at 298 K. This value was much higher than those reported previously and those observed in this work for the original MIL-101(Cr) or MIL-53(Al). These results demonstrated that the hybrid of MIL-101(Cr) and MIL-53(Al) was a promising material for selective CO2 capture from natural and biogas.
| S-EPMC9064224 | biostudies-literature
Project description:Metal organic frameworks (MOFs) with many unique advantages have drawn wide attention in the field of catalysis. However, the poor structural stability of MOFs limits its application. Heat treatment for MOFs can enhance its electrical conductivity and structural stability, which helps to improve the catalytic performance. Ni nanoparticles supported on MIL-53(Al) were synthesized through different heat treatment temperature. Catalysts with uniform distribution of active nickel and rich mesoporous structure were obtained by adjusting the heat treatment temperature to 500 °C. The results show this catalyst has the best hydrogenation activity and stability. Under the reaction conditions of 60 °C and 2 h, the conversion rate of DCPD is 100%, and the selectivity of endo-THDCPD is higher than 95%. After five cycles, the catalyst also show excellent stability and high activity, the conversion rate of DCPD is still 100%.
| S-EPMC8985133 | biostudies-literature
Project description:A chromium-containing metal-organic framework (MOF), MIL-101 (Chromium(III) benzene-1,4-dicarboxylate), was used to catalyze the one pot, three component synthesis of some 2,4,5-trisubstituted imidazoles under solvent-free conditions. The advantages of using this heterogeneous catalyst include short reaction time, high yields, easy and quick isolation of catalyst and products, low amount of catalyst needed, and that the addition of solvent, salt, and additives are not needed. This catalyst is highly efficient and can be recovered at least 5 times with a slight loss of efficiency. The structure of the metal-organic frameworks (MOF) was confirmed by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (HNMR) were performed to confirm some of the synthesized products. Experimental data indicated that the optimum amount of catalyst was 5 mg for benzil (1 mmol), 4-chlorobenzaldehyde (1 mmol), and ammonium acetate (2.5 mmol), and the synthetic route to the various imidazoles is performed in 10 min by 95% yield, an acceptable result rivalling those of other catalysts.
| S-EPMC8067193 | biostudies-literature
Project description:In this study, metal-organic framework MIL-53(Al) was synthesized and studied to understand the different mechanisms between normal MIL-53(Al) and 2D metal-organic framework MIL-53(Al) for removing fluoride. Comparatively, the 2D MIL-53(Al) had two-dimensional linear morphology rather than block shape, indicating more expose adsorptive sites than normal MIL-53(Al). The batch adsorption experiments were applied to investigate the performance of 2D MIL-53(Al), including pH, adsorption kinetics, and thermodynamics. The 2D MIL-53(Al) (75.50 mg/g) showed better adsorption capacity than normal MIL-53(Al) (35.63 mg/g). The adsorption process of 2D MIL-53(Al) followed the pseudo-first-order model and Langmuir model. The adsorption mechanism of this material was further studied by using experimental characterization and density functional theory calculations in detail. The main adsorptive sites were Al and O in the 2D MIL-53(Al), and the relationship between fluoride binding with Al and O was HF2 - > HF > F-. The species of fluoride were HF2 -, HF, F at different pH and concentrations. Hence, this study provides a significant way on the application of two-dimensional materials for removing fluoride.
| S-EPMC9488010 | biostudies-literature
Project description:A promising hierarchical nanocomposite of MIL-53(Al)/ZnO was synthesized as a visible-light-driven photocatalyst to investigate the degradation of amoxicillin (AMX). MIL-53(Al)/ZnO ultrafine nanoparticles were obtained by preparing Zn-free MIL-53Al and employing it as a reactive template under hydrothermal and chemical conditions. The synthesized nanocomposite (MIL-53(Al)/ZnO) has a low content of Al > 1.5% with significantly different characterizations of the parent compounds elucidated by various analyses such as SEM, TEM, XRD, EDX, and UV-Vis. The effect of operational parameters (catalyst dose (0.2-1.0 g/L), solution pH (3-11), and initial AMX concentration (10-90 mg/L)) on the AMX removal efficiency was studied and optimized by the response surface methodology. A reasonable goodness-of-fit between the expected and experimental values was confirmed with correlation coefficient (R2) equal to 0.96. Under the optimal values, i.e., initial AMX concentration = 10 mg/L, solution pH ~ 4.5, and catalyst dose = 1.0 g/L, 100% AMX removal was achieved after reaction time = 60 min. The degradation mechanism and oxidation pathway were vigorously examined. The AMX degradation ratios slightly decreased after five consecutive cycles (from 78.19 to 62.05%), revealing the high reusability of MIL-53(Al)/ZnO. The AMX removal ratio was improved with enhancers in order ([Formula: see text]> H2O2 > S2O8-2). The results proved that 94.12 and 98.23% reduction of COD were obtained after 60 and 75 min, respectively. The amortization and operating costs were estimated at 3.3 $/m3 for a large-scale photocatalytic system.
| S-EPMC9508224 | biostudies-literature
Project description:The topological metal-organic framework isomers MIL-53 and MIL-68 form from similar educts but differ in their pore geometries. They have been known for several years, but their synthesis is always reported separately. In consequence, the underlying mechanism and decisive synthesis parameters leading to the formation of either MIL-53 or MIL-68 are not understood. The present study shows how to induce the formation of MIL-68(Al) rather than MIL-53(Al) at low synthesis temperatures in N,N-dimethylformamide (DMF) using a modulated synthesis approach. MIL-68(Al) is identified as the intermediate product of formic acid modulated synthesis, which converts into the thermodynamically stable MIL-53(Al) product at longer synthesis times. The interactions of formic acid with the synthesis precursors responsible for inducing MIL-68(Al) formation are investigated with in situ Raman and FTIR spectroscopy. In contrast to the commonly assumed modulation mechanism of competitive coordination of linker and modulator with the metal node, formic acid is shown to form hydrogen bonds via the carboxylic group of the terephthalic acid (H2BDC) linker, slowing prenucleation building unit and subsequent crystal growth. MIL-68(Al) formation is favored by the combination of a deficiency of terephthalic acid in solution and a slow MOF growth rate. Dissolved H2BDC in solution is proposed to hinder MIL-68(Al) formation by serving as a molecular template for the rhombic MIL-53(Al) pore channels.
| S-EPMC9049789 | biostudies-literature
Project description:Herein is reported the utilization of acetonitrile as a new solvent for the synthesis of the three significantly different benchmark metal-organic frameworks (MOFs) CAU-10, Ce-UiO-66, and Al-MIL-53 of idealized composition [Al(OH)(ISO)], [Ce6 O4 (OH)4 (BDC)6 ], and [Al(OH)(BDC)], respectively (ISO2- : isophthalate, BDC2- : terephthalate). Its use allowed the synthesis of Ce-UiO-66 on a gram scale. While CAU-10 and Ce-UiO-66 exhibit properties similar to those reported elsewhere for these two materials, the obtained Al-MIL-53 shows no structural flexibility upon adsorption of hydrophilic or hydrophobic guest molecules such as water and xenon and is stabilized in its large-pore form over a broad temperature range (130-450?K). The stabilization of the large-pore form of Al-MIL-53 was attributed to a high percentage of noncoordinating -COOH groups as determined by solid-state NMR spectroscopy. The defective material shows an unusually high water uptake of 310?mg?g-1 within the range of 0.45 to 0.65?p/p°. In spite of showing no breathing effect upon water adsorption it exhibits distinct mechanical properties. Thus, mercury intrusion porosimetry studies revealed that the solid can be reversibly forced to breathe by applying moderate pressures (?60?MPa).
| S-EPMC7154691 | biostudies-literature