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Olefin/paraffin separations are among the most energy-intensive processes in the petrochemical industry, with ethylene being the most widely consumed chemical feedstock. Adsorptive separation utilizing molecular sieving adsorbents can optimize energy efficiency, whereas the size-exclusive mechanism alone cannot achieve multiple olefin/paraffin sieving in a single adsorbent. Herein, an unprecedented sieving adsorbent, BFFOUR-Cu-dpds (BFFOUR = BF4-, dpds = 4,4'-bipyridinedisulfide), is reported for simultaneous sieving of C2-C4 olefins from their corresponding paraffins. The interlayer spaces can be selectively opened through stronger guest-host interactions induced by unsaturated C = C bonds in olefins, as opposed to saturated paraffins. In equimolar six-component breakthrough experiments (C2H4/C2H6/C3H6/C3H8/n-C4H8/n-C4H10), BFFOUR-Cu-dpds can simultaneously divide olefins from paraffins in the first column, while high-purity ethylene (> 99.99%) can be directly obtained through the subsequent column using granular porous carbons. Moreover, gas-loaded single-crystal analysis, in-situ infrared spectroscopy measurements, and computational simulations demonstrate the accommodation patterns, interaction bonds, and energy pathways for olefin/paraffin separations. Olefin/paraffin separations are challenging in chemical industry. Here, authors report a sieving adsorbent for separating C2-C4 olefins from counterpart paraffins. The interlayer spaces are selectively opened via stronger guest-host interactions induced by olefins, as opposed to saturated paraffins. [ABSTRACT FROM AUTHOR]

Molecular sieving of propylene (C 3 H 6 ) from propane (C 3 H 8 ) is highly demanded for C 3 H 6 purification. However, delicate control over aperture size to achieve both high C 3 H 6 uptake and C 3 H 6 /C 3 H 8 selectivity with low cost remains a significant challenge. Herein, a green and scalable approach is reported for preparing an isomeric CALF-20 adsorbent, termed as NCU-20, using water as the only solvent with a cost of $10 per kilogram. NCU-20 features a contracted pore size (4.2 × 4.7 Å 2 ) compared to CALF-20 (5.2 × 5.7 Å 2 ), which enables molecular sieving of C 3 H 6 (4.16 × 4.65 Å 2 ) from C 3 H 8 (4.20 × 4.80 Å 2 ). Notably, NCU-20 exhibits record-high C 3 H 6 adsorption capacity (94.41 cm 3  cm -3 ) at 298 K and 1.0 bar, outperforming all C 3 H 6 /C 3 H 8 molecular sieving adsorbents. The sieving performances of C 3 H 6 /C 3 H 8 are well maintained at elevated temperatures. Therefore, a delicate balance between C 3 H 6 adsorption capacity (91.62 cm 3  cm -3 ) and C 3 H 6 /C 3 H 8 selectivity (uptake ratio of 22.2) is obtained on NCU-20 at 298 K and 0.5 bar. Furthermore, dynamic breakthrough experiments demonstrate a high productivity of 65.39 cm 3  cm -3 for high-purity C 3 H 6 (>99.5%) from an equimolar C 3 H 6 /C 3 H 8 gas-mixture., (© 2024 Wiley‐VCH GmbH.)