Abstract
Since ethylene (C(2)H(4)) is important feedstock in the chemical industry, developing economical and energy-efficient adsorption separation techniques based on ethane (C(2)H(6))-selective adsorbents to replace the energy-intensive cryogenic distillation is highly demanded, which however remains a daunting challenge. While previous anionic boron cluster hybrid microporous materials display C(2)H(4)-selective features, we herein reported that the incorporation of a neutral para-carborane backbone and aliphatic 1,4-diazabicyclo[2.2.2]octane (DABCO) enables the reversed adsorption of C(2)H(6) over C(2)H(4). The generated carborane-hybrid microporous material ZNU-10 (ZNU = Zhejiang Normal University) is highly stable in humid air and maintains good C(2)H(6)/C(2)H(4) separation performance under high humidity. Gas loaded single crystal structure and density-functional theory (DFT) calculations revealed that the weakly polarized carborane and DABCO within ZNU-10 induce more specific C-H(δ+)⋯H(δ-)-B dihydrogen bonds and other van der Waals interactions with C(2)H(6), while the suitable pore space allows the high C(2)H(6) uptake. Approximately 14.5 L kg(-1) of polymer grade C(2)H(4) can be produced from simulated C(2)H(6)/C(2)H(4) (v/v 10/90) mixtures under ambient conditions in a single step, comparable to those of many popular materials.