Twisted pore aperture of MOF induced three-dimensional restricted sieving separation for CO2 and C2H2 mixtures

Deep purification of perfluorinated electronic specialty gas with a scalable metal-organic framework featuring tailored positive potential traps

The sequestration of trace hexafluoropropylene (C3F6) is a critical yet formidable task in the production of high-purity perfluoropropane (C3F8), an important perfluorinated electronic specialty gas (F-gas) in the advanced electronics industry. Traditional adsorbents struggle with uneven, low-pressure uptake and compromises in selectivity. This work utilizes aperture size-electrostatic potential matching within a robust metal-organic framework (Al-PMA) to facilitate selective, reversible binding of C3F6 while excluding larger C3F8 molecules. The presence of bridging hydroxyl groups (μ2-OH) in Al-PMA creates positive electrostatic potential traps that securely anchor C3F6 through strong hydrogen bonding, evidenced by in-situ infrared and 19F magic angle spinning nuclear magnetic resonance spectroscopy. Breakthrough experiments demonstrate the efficient removal of trace C3F6 from C3F8 under ambient conditions, achieving C3F8 purity exceeding 99.999%. The scalability of Al-PMA synthesis, remarkable stability, and exceptional performance highlight its potential as a promising adsorbent for industrial C3F6/C3F8 separations.

Economically Scalable Cu-based MOFs: Vital Role of Structural Integrity towards Selectivity on Azeotropic Ethanol Dehydration

A facile, green, and economical method for the scalable synthesis of hydrophilic copper-triazole metal-organic frameworks (Cu-trz) is demonstrated. Numerous open metal sites within the highly crystalline porous structure of Cu-trz are generated through mild thermal activation, enabling its application in liquid-phase ethanol dehydration under ambient conditions. The frameworks with distinct crystallinity and particle sizes were achieved by modifying the synthesis process. The high crystallinity of the framework plays an exclusive role in enhancing water adsorption capacity. With selective water adsorption comparable to commercial zeolite 3 A, Cu-trz MOF emerges as a promising candidate for cost-effective water-ethanol separation.

Fluorinated MOF-Based Hexafluoropropylene Nanotrap for Highly Efficient Purification of Octafluoropropane Electronic Specialty Gas

High-purity octafluoropropane (C3F8) electronic specialty gas is a key chemical raw material in semiconductor and integrated circuit manufacturing industry, while selective removal of hexafluoropropylene (C3F6) impurity for C3F8 purification is essential but a challenging task. Here we report a fluorinated cage-like MOF Zn-bzc-CF3 (bzc=5-(trifluoromethyl)-1H-pyrazole-4-carboxylic acid) for C3F6/C3F8 separation. The incorporation of -CF3 groups not only provides suitable pore aperture size for highly efficient size-exclusive C3F6/C3F8 separation, but also creates hydrophobic microenvironments, endowing Zn-bz-CF3 high chemical stability. Remarkably, Zn-bzc-CF3 exhibits high C3F6 adsorption capacity while excluding C3F8, achieving ideal molecular-sieving C3F6/C3F8 separation. Breakthrough experiments show that Zn-bzc-CF3 can efficiently separate C3F6/C3F8 mixture and high-purity C3F8 (99.9 %) can be obtained.