摘要
The exploration of ethane(C_(2)H_(6))-selective porous materials for the direct production of polymer-grade ethylene(C_(2)H_(4))from a C_(2)H_(6)/C_(2)H_(4) mixture in a single energy-saving adsorption step is of utmost importance but remains a significant challenge.Thus,developing robust C_(2)H_(6)-selective adsorbents with high C_(2)H_(6) capacity and C_(2)H_(6)/C_(2)H_(4) selectivity is urgently needed for industrial applications.In this study,we have successfully designed and synthesized two novel calix[4]resorcinarene-based porous organic cages(POCs)named CPOC-501 and CPOC-502.The POCs were formed via a Schiff-base reaction involving face-directed[6+8]condensation between a bowlshaped tetratopic tetraformylcalix[4]resorcinarene and triangular tritopic amine synthons.Analysis using single crystal X-ray crystallography revealed that both cages possess large truncated octahedral cavities with a volume of approximately 6500Å3 and 12 accessible rhombic windows with a side length of approximately 10.5Å.Furthermore,the cages exhibited excellent chemical stability under neutral,acidic,and basic conditions and high Brunauer–Emmett–Teller specific surface areas of up to 2175 m^(2) g^(−1) after desolvation.Both POCs demonstrated superior adsorption capabilities for C_(2)H_(6) over C_(2)H_(4).Notably,CPOC-502 exhibited a C_(2)H_(6) capacity and C_(2)H_(6)/C_(2)H_(4) selectivity of 83 cm^(3) g^(−1) and 2.83,respectively,surpassing most of the best-performing C_(2)H_(6)-selective porous organic materials reported to date.Moreover,breakthrough experiments confirmed that both cages efficiently produced polymer-grade C_(2)H_(4)(>99.9%)directly from the C_(2)H_(6)/C_(2)H_(4) mixture,highlighting their outstanding recyclability.
基金
financially supported by the National Nature Science Foundation of China(grant nos.22071244 and 22275191)
the Youth Innovation Promotion Association CAS(grant no.2022305)
the Natural Science Foundation of Fujian Province of China(grant nos.2022J01503,2020J05087,and 2022I0037).
