CO₂ Separation by Imide/Imine Organic Cages

Abstract

Two novel imide/imine-based organic cages have been prepared and studied as materials for the selective separation of CO 2 from N 2 and CH 4 under vacuum swing adsorption conditions. Gas adsorption on the new compounds showed selectivity for CO 2 over N 2 and CH 4 . The cages were also tested as fillers in mixed-matrix membranes for gas separation. Dense and robust membranes were obtained by loading the cages in either Matrimid® or PEEK-WC polymers. Improved gas-transport properties and selectivity for CO 2 were achieved compared to the neat polymer membranes.

Mixed Matrix Membranes Using Porous Organic Polymers (POPs)—Influence of Textural Properties on CO2/CH4 Separation

“…The exception to this behavior corresponded to the POP-6-filled MMMs that deviated from the ideal morphology described by the Maxwell model, which can be attributed to the higher porosity afforded by this POP6 to the heterogeneous structure of the MMMs when compared to the other MMMs in this work. These observations agree with data from the literature for other organic cage fillers and PEEK-WC, compared with Matrimid, in MMMs for gas separation [21].…”

“…These behavioral observations are attributed to the high CO 2 uptake and differences in the porosity of the POP fillers, with POP6 being larger than the others, and to the dependence of diffusivity on permeability through rigid Matrimid polyimide membranes [21,24], and to the gas solubility that is probably facilitating CO 2 transport through such hydrophilic polymers as Pebax and CS:PVA [28].…”

Porous Metal‐Organic Cages Based on Rigid Bicyclo[2.2.2]oct‐7‐ene Type Ligands: Synthesis, Structure, and Gas Uptake Properties

“…This moiety was recently used in the formation of porous organic cages prepared via condensation reactions with polyamines, with the rigidity of the unit sufficient to maintain the pore of the cage molecules. [13] In our work, the bicyclo[2.2.2]oct‐7‐ene units provide the curvature needed for the lantern geometry of metal‐organic cages. The three examples of lantern‐type metal‐organic cages we detail are found to sustain elongation or compression along the inter‐paddlewheel axis, affecting the size of the cavity in the molecules.…”

Influence of the solvent in the self-assembly and binding properties of [1 + 1] tetra-imine bis-calix[4]pyrrole cages

“…These singular features make cage containers attractive molecular designs for different applications such as molecular recognition, [3][4][5] stabilization of reactive species 6 and mediation of chemical reactivity, 7,8 among others. [9][10][11][12] The rst examples of molecular cages date back to the middle 80s'. In pioneering works, Cram 13 and Collet 14 reported the preparation of molecular containers using exclusively irreversible covalent bonds.…”

“…These singular features make cage containers attractive molecular designs for different applications such as molecular recognition, 3–5 stabilization of reactive species 6 and mediation of chemical reactivity, 7,8 among others. 9–12…”