469122 Synthesis of MOF-74(Ni) Using Segmented-Flow and Microwave-Assisted Methods with Chemical Modulation
The segmented-flow, microwave-assisted approach can be used to potentially support production of nanomaterials which still face commercialization difficulties due to the lack of scalable synthetic approaches, including metal-organic frameworks (MOFs).7 MOFs are of considerable scientific and technological interest due to the flexibility in modifying their properties by changing either metal coordination species and/or organic linkers. MOFs can have three dimensional long-range order, high-surface area, large internal free volume space, and tunable adsorption properties. MOFs may be used in a wide range of applications including: gas storage, separation, catalysis, and more recently pharmaceuticals. However, the lack of scalable synthetic approaches still limits MOF production at industrial scales. In this study, we demonstrate the synthesis of MOF-74(Ni) using a segmented-flow, microwave-assisted reactor. The reaction chemistries were optimized so that the synthesis can be performed under relatively mild conditions. High yields (> 95 %) were obtained for short reaction times (~15 minutes), as opposed to days for typical batch reaction conditions. Optimization of reaction parameters for the microwave reactor has led to improvements in MOF crystallinity, conversion efficiencies, and production rates (> 4 g/h). We have found that chemical modulators significantly reduce the particle size distribution, increase the effective particle size, and enhance the adsorption properties of the MOFs. Characterization of the MOFs was performed using powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, BET isotherms, and UV-Vis spectroscopy to evaluate effects of microwave temperature and chemical modulator concentrations on MOF-74(Ni) properties.
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