1,3-Diyne-Linked Conjugated Microporous Polymer for Selective CO₂ Capture

In this work, we demonstrate that the introduction of pyrene and alkyne groups into a highly conjugated microporous polymer (LKK-CMP-1) can be achieved via oxidative homocoupling of 1,3,6,8-tetraethynylpyrene ( L ). The 1,3-diyne-linked conjugated microporous polymer not only has good thermal stability but also has small pore sizes. These small pores within LKK-CMP-1 facilitate the interactions between CO 2 and its pore walls, evidenced by the high isosteric heats of adsorption of CO 2 and also confirmed by ideal-adsorption-solution-theory (IAST) calculations based on single-component-isotherm data. Therefore, despite moderate CO 2 adsorption uptake (9.78 wt %, 273 K, and 1 bar) and isosteric heat of adsorption (35.0 kJ mol –1 ) for CO 2, LKK-CMP-1 still exhibits excellent selectivities of CO 2 /N 2 (44.2) and CO 2 /CH 4 (8.2) at molar ratios of 15:85 and 20:80 respectively. In addition, breakthrough experiments have also shown that LKK-CMP-1 is an effective material for CO 2 /N 2 and CO 2 /CH 4 separations under flowing conditions.