There are great challenges in developing efficient adsorbents to replace the currently used and energy-intensive cryogenic distillation processes for olefin/paraffin separation, owing to the similar physical properties of the two molecules. Here we report an ultramicroporous metal–organic framework [Ca(C₄O₄)(H₂O)], synthesized from calcium nitrate and squaric acid, that possesses rigid one-dimensional channels. These apertures are of a similar size to ethylene molecules, but owing to the size, shape and rigidity of the pores, act as molecular sieves to prevent the transport of ethane. 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, which is 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.

由于两种分子的相似的物理性质，在开发有效的吸附剂以替代当前用于烯烃/石蜡分离的耗能的低温蒸馏方法方面存在着巨大的挑战。在这里，我们报道了一种超微孔金属-有机骨架[Ca（C ₄ O ₄）（H ₂O）]，由硝酸钙和方酸合成而成，具有刚性的一维通道。这些孔具有与乙烯分子相似的尺寸，但是由于孔的尺寸，形状和刚度，它们用作防止乙烷运输的分子筛。该分子筛用于分离乙烯/乙烷混合物的效率通过在环境条件下具有高乙烯生产率的突破性实验得到验证。这种材料可以使用环保方法轻松地以千克规模合成，并且是水稳定的，这对于潜在的工业实施非常重要。使用具有明确和刚性孔的高刚性金属有机框架的策略也可以扩展到其他多孔材料，以进行化学分离过程。