Propane-selective porous materials for inverse propane/propylene separation

Propane/propylene splitting is among the most energy- and capital-intensive separations in the petrochemical industry, yet it is indispensable for upgrading mixed C3 cuts to polymer-grade propylene. Because propane and propylene exhibit nearly overlapping physicochemical properties, conventional cryogenic distillation requires very large columns, high reflux ratios, and substantial thermal duties. Adsorption-based separations using porous solids offer a compelling non-cryogenic alternative, especially when the adsorbent is propane-selective (inverse-selective). Propane is retained as the impurity and high-purity propylene can be delivered directly as the raffinate, potentially simplifying process flowsheets and reducing regeneration penalties associated with product-capture schemes. This Review summarizes recent advances, primarily from 2019 to early 2026, in propane-selective porous materials for inverse propane/propylene separation, with metal-organic frameworks (MOFs) as the central focus and porous carbons, hydrogen-bonded organic frameworks (HOFs), and covalent organic frameworks (COFs) discussed as complementary families, while earlier landmark studies such as ZIF-8 are included where necessary for historical context. We highlight how pore-surface polarity/hydrophobicity, ultramicropore confinement, cooperative weak interactions, and framework dynamics can invert the conventional olefin preference and enhance propane capture within practical operating windows. Emphasis is placed on application-relevant evaluation, including gas adsorption, fixed-bed breakthrough behavior, working capacity, regenerability, tolerance to humidity and trace impurities, cycling durability, and prospects for scalable shaping and process integration.