Phosphine-containing microporous networks: High selectivity toward carbon dioxide to methane

Two phosphine-containing microporous organic networks TPPDEB-O and TPPDEB-S were designed and synthesized via Sonogashira–Hagihara coupling condensation reaction. The electronic structures and the adsorption characteristics of the polymers can be tailored by facile oxidation and vulcanization modification of the nucleophilic phosphorus atom node. Nitrogen adsorption–desorption isotherms of TPPDEB-O and TPPDEB-S showed the Brunauer–Emmet–Teller specific surface areas were 712.51 m2 g−1 and 677.02 m2 g−1, respectively. The two frameworks have strong affinity for CO2 and the isosteric heats of sorption were excess 25 KJ mol−1 at the whole loading range. Furthermore, their selectivity toward CO2/CH4 exceeded most of porous organic polymers and the surfaces functionalized by PO or PS showed a large different capacity on the CO2/CH4 separation (TPPDEB-O and TPPDEB-S at 273 K is 15.9, 5.5 and at 298 K is 9.3, 4.3, respectively).