Reactive Chlorine Capture by Dichlorination of Alkene Linkers in Metal–Organic Frameworks

Abstract

Chlorine (Cl2) is a toxic and corrosive gas that is both an essential reagent in industry and a potent chemical warfare agent. Materials that can strongly bind Cl2 at low pressures are essential for industrial and civilian personal protective equipment (PPE). Herein, we report the first examples of irreversible Cl2 capture via the dichlorination of alkene linkages in Zr-based metal–organic frameworks. Frameworks constructed from fumarate (Zr-fum) and stilbene (Zr-stilbene) linkers retain long-range order and accessible porosity after alkene dichlorination. In addition, energy-dispersive X-ray spectroscopy reveals an even distribution of Cl throughout both materials after Cl2 capture. Cl2 uptake experiments reveal high irreversible uptake of Cl2 (>10 wt %) at low partial pressures (<100 mbar), particularly in Zr-fum. In contrast, traditional porous carbons mostly display reversible Cl2 capture, representing a continued risk to users after exposure. Overall, our results support that alkene dichlorination represents a new pathway for reactive Cl2 capture, opening new opportunities for binding this gas irreversibly in PPE.

Modulated self-assembly ofhcptopology MOFs of Zr/Hf and the extended 4,4′-(ethyne-1,2-diyl)dibenzoate linker

“…We and others have previously shown that MOFs linked by ligands with internal alkene 12,45–48 and alkyne 12,13,49,50 subunits can be postsynthetically modified by halogenation. Specifically, we have demonstrated that the Zr( iv ) and Hf( iv ) fcu phases linked by EDB 2− can be quantitatively brominated in a single-crystal to single-crystal manner.…”

“…This combination of high porosity and significant defectivity indicates the potential for application of the GUF-12 congeners in catalysis. 33 We and others have previously shown that MOFs linked by ligands with internal alkene 12,[45][46][47][48] and alkyne 12,13,49,50 subunits can be postsynthetically modified by halogenation. Specifically, we have demonstrated that the Zr(IV) and Hf(IV) fcu phases linked by EDB 2− can be quantitatively brominated in a single-crystal to single-crystal manner.…”

Research Progress of Materials Used for Elemental Halogen Capture

“…MOF 对惰性气体和活性气体储存的有效性已被广 泛证明 [49][50] , 不仅有许多研究表明 MOF 可以吸附和储 存强氧化性或腐蚀性气体, 如 O 2 [51] 、NO [52] 、SO 2 [53] 和 NH 3 [54] , 还 有 一 些 研 究 表 明 含 胺 基 的 MOF 如 UIO-66-NH 2 、Al-MIL-53-NH 2 和 MOF-5-NH 2 以及含烯 烃的 MOF 如 Zr-fum 和 Zr-stilbene [55][56][57]…”

Tandem Efficient Bromine Removal and Silver Recovery by Resorcinol-Formaldehyde Resin Nanoparticles

“…To demonstrate this concept, aromatic resorcinol-formaldehyde (RF) resin polymer nanoparticles (NPs) with abundant aromatic groups, were selected as a bromination model, where RF is often served as a template, sacrificial layer, or precursor for carbon materials to build versatile nanostructures. − As schematically illustrated in Figure a–c, the pristine RF NPs are expected to achieve efficient Br 2 fixation through both electrophilic substitution in phenol analogs and radical substitution in benzyl positions (Figure c) . It has been proven effective to achieve reactive chlorine capture through electrophilic aromatic substitution or unsaturated alkene dichlorination by using aromatic-ligand-containing MOFs, − which avoids the potential risk of Cl 2 exposure by traditional porous carbons with a reversible Cl 2 capture mechanism. Moreover, the bromination process produces high value-added chemicals, including both brominated aromatic resins and hydrobromic acid (HBr).…”