Tertiary-Amine-Functional\nPoly(arylene ether)s for\nAcid-Gas Separations

Competitive sorption enables the emergent phenomenon\nof enhanced\nCO<sub>2</sub>-based selectivities for gas separation membranes when\nusing microporous polymers with primary amines. However, strong secondary\nforces in these polymers through hydrogen bonding results in low solvent\nsolubility, precluding standard solution processing approaches to\nform these polymers into membrane films. Herein, we circumvent these\nmanufacturing constraints while maintaining competitive-sorption enhancements\nby synthesizing eight representative microporous poly(arylene ether)s\n(PAEs) with tertiary amines. High-pressure H<sub>2</sub>S, CO<sub>2</sub>, and CH<sub>4</sub> sorption isotherms were collected for\nthese samples to demonstrate enhanced affinity for acid gases relative\nto the unfunctional control polymer. Although competitive sorption\nwas observed for all samples, improvements were less pronounced than\nfor primary-amine-functional analogs. For H<sub>2</sub>S-based separations,\nthe benefits of competitive sorption offset decreases in selectivity\ndue to plasticization. This detailed study helps to elucidate the\nrole of tertiary amines for acid gas separations in solution-processable\nmicroporous PAEs.