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There are great challenges in developing efficient adsorbents to replace currently used and energy-intensive cryogenic distillation processes for olefin/paraffin separations, due to the similar physical properties of the two molecules. We report an ultramicroporous metal-organic framework [Ca(C4)4)(H2O)], synthesized from calcium nitrate and squaric acid, featuring rigid one dimensional channels that have apertures of a similar size to ethylene molecules, but act as molecular sieves that prevent transport of ethane, resulting from the size, shape, and pore rigidity of this material. The efficiency of this molecular sieve for the separation of ethylene/ethane mixtures is validated by breakthrough experiments with high ethylene productivity under ambient conditions. This material can be easily synthesized at the kilogram scale using an environmentally friendly method, and is water-stable, important for potential industrial implementation. The strategy of using highly rigid metal-organic frameworks with well-defined and rigid pores could also be extended to other porous materials for chemical separation processes.
Lin, R.
, Li, L.
, Zhou, H.
, Wu, H.
, He, C.
, Li, S.
, Krishna, R.
, Li, J.
, Zhou, W.
and Chen, B.
(2018),
Molecular Sieving of Ethylene from Ethane using a Rigid Metal-Organic Framework, Nature Materials, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=926818
(Accessed October 20, 2025)