Dual pore‐size sieving in a novel oxygenate‐pillared microporous adsorbent for C6 alkane isomers separation

Abstract

AbstractAdsorbents executing molecular sieving mechanisms for the efficient separation of n‐hexane (C6) alkane isomers require delicate pore size control, but afford unsatisfactory single‐component separations according to their branch degrees. Herein, we report a novel oxygenate‐pillared microporous adsorbent, MoOFOUR‐Co‐tpb, ([Co(tpb)2MoO4], tpb = 1,2,4,5‐tetra(pyridin‐4‐yl) benzene), with three gourd‐shaped channels for dual pore‐size sieving of C6 isomers. In particular, MoOFOUR‐Co‐tpb excludes 2,2‐dimethylbutane, while 3‐methylpentane (3MP) can enter one channel showing a high uptake of 82.6 mg g−1, contrasting to the n‐hexane (nHEX) adsorption by two channels (136 mg g−1). This dual pore‐size control strategy renders a record high equilibrium–kinetic combined selectivity for nHEX/3MP (30.2). Moreover, three‐ and five‐component breakthrough experiments confirm the practical separation performances and cycling stability. Multiple theoretical simulations reveal the separation mechanism and adsorption sites.