Significantly enhanced gas separation properties of microporous membranes by precisely tailoring their ultra-microporosity through bromination/debromination

Recent advances in structurally elaborate triptycenes, triptycene-containing polymers and assemblies: structures, functions and applications

“…13) [9,18] (39) with ortho-bromo groups and pyromellitic anhydride (202) showed ca. 8 times greater gas permeability than corresponding polyimide devoid of bromo groups [38]. Moreover, when the poly-23 membrane was heated to °C, debromination occurred yielding a carbon molecular-sieve membrane, which displayed an almost 9-fold increase in gas permeability while maintaining permselectivity, with CO 2 /N 2 and CO 2 /CH 4 selectivities of 29.2 and 30.9, respectively, and an unprecedentedly CO 2 permeability coefficient of 20639 barrer [38].…”

“…These compounds have also been synthesized by other methods [34] and will be described later. Nitration and reduction of 2,6(,7)-dihydroxytriptycene (34,35) yields a trip-monomer with two hydroxy and two amino groups (38) [33]. This type of monomer is important in the preparation of polybenzimidazoles [35] through thermal rearrangement to the corresponding hydroxy group-containing polyimides, which have been shown to act as excellent gas-separation membranes [36].…”

“…This type of monomer is important in the preparation of polybenzimidazoles [35] through thermal rearrangement to the corresponding hydroxy group-containing polyimides, which have been shown to act as excellent gas-separation membranes [36]. Another monomer related to gas separation membranes, the di-ortho-brominated 2,6(,7)-diaminomonomer (39), which is useful in the synthesis of polyimides with reduced free rotation, has recently been reported [37,38]. A route to synthesize triaminotriptycenes via Beckmann-rearrangement (40) from acetylated triptycenes (23)(24)(25)(26)(27)(28)(29)(30)(31)(32) is also known [27].…”

Next-generation carbon molecule sieve membranes derived from polyimides and polymers of intrinsic microporosity for key energy intensive gas separations and carbon capture

“…35 In the past few decades, large progress has been made in PI- and PIM-based CMS membranes, 55,56 and numerous PIs and PIMs with different chemical structures have been designed with the aim of promoting CMS separation performance. 57–59 In addition, different CMS pyrolysis protocols have been developed but a relevant review is still lacking. Therefore, in the current work, the effects of pyrolysis parameters including pyrolysis temperature, ramping rate, pyrolysis atmosphere and soaking time on the pore structure and gas separation performance of PI based CMS membranes were systematically summarized and discussed.…”

Direct Thermal Oxidative Cross-Linking in Air toward Hierarchically Microporous Polymer Membranes for Advanced Molecular Sieving

“…Herein, we explore a combination of triptycene and Tröger’s base structural polyimides and thermal oxidative cross-linking, whereby the hierarchically microporous structure is induced by oxidative chain scission and cross-linking, leading to dramatically enhanced gas transport properties. Due to the rigid and three-dimensional (3D) structures, triptycene − and Tröger’s base , moieties have been extensively incorporated in gas separation membranes by inhibiting segmental packing and introducing fractional free volumes. In particular, we report the fabrication of triptycene and Tröger’s base-based polyimides and the direct thermal oxidative treatment of the pristine membranes in air.…”