Delayed Linker Addition (DLA) Synthesis for Hybrid SOD ZIFs with Unsubstituted Imidazolate Linkers for Propylene/Propane and n‐Butane/i‐Butane Separations. (18th March 2021)

• Record Type: Journal Article
• Authors: Hillman, Febrian; Hamid, Mohamad Rezi Abdul; Krokidas, Panagiotis; Moncho, Salvador; Brothers, Edward N.; Economou, Ioannis G.; Jeong, Hae‐Kwon
• Is Part Of: Angewandte Chemie. Volume 133:Number 18(2021)
• Page Start: 10191
• Page End: 10199
• Publication Date: 2021-03-18
• Subjects: gas separations -- hybrid metal–organic frameworks -- hybrid zeolitic–imidazolate frameworks -- linker doping; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202015635
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: We present a novel synthesis strategy termed delayed linker addition (DLA) to synthesize hybrid zeolitic‐imidazolate frameworks containing unsubstituted imidazolate linkers (Im) with SOD topology (hereafter termed Im/ZIF‐8). Im linker incorporation can create larger voids and apertures, which are important properties for gas storage and separation. To date, there have been only a handful of reports of Im linkers incorporated into ZIF‐8 frameworks, typically requiring arduous and complicated post synthesis approaches. DLA, as reported here, is a simple one‐step synthesis strategy allowing high incorporation of Im linker into the ZIF‐8 framework while still retaining its SOD topology. We fabricated mixed‐matrix membranes (MMMs) with 6FDA‐DAM polymer and Im/ZIF‐8 obtained via DLA as a filler. The Im/ZIF‐8‐containing MMMs showed excellent performance for both propylene/propane and n‐butane/i‐butane separation, displaying permeability and ideal selectivity well above the polymer upper bound. Moreover, highly detailed molecular simulations shed light to the aperture size and flexibility response of Im/ZIF‐8 and its improved diffusivity as compared to ZIF‐8. Abstract : A simple one‐pot synthesis, termed delayed linker addition (DLA), was developed to form hybrid ZIFs consisting of unsubstituted imidazolate and 2‐methylimidazolate linkers with SOD topology. The easily obtained nuclei of ZIF‐8 were utilized as a template to guide the structure of the crystals and to reduce the high energy required to form hybrid ZIFs.