Hydrophobic Pores in a Calcium-Based MOF Enable One-Step Ethylene Purification from C₂H₂/CO₂/C₂H₄ Mixtures

Abstract

We report here the construction of a microporous calcium-based metal-organic framework based on methyl-functionalized tetracarboxylate linker. The compound, HIAM-204, features hydrophobic pores exhibiting precise size/shape compatibility towards C₂H₂ and CO₂, affording high low-pressure (0.10 bar) adsorption capacities and enabling one-step ethylene purification from C₂H₂/CO₂/C₂H₄ mixtures.Ethylene (C2H4) is a key feedstock for the production of various polymers and valuable chemicals, such as polyethylene, detergents, and coatings. 1,2 However, the production processes of C2H4 often generate byproducts such as acetylene (C2H2) and carbon dioxide (CO2), which must be removed to obtain polymer-grade C2H4 for downstream uses. [3][4][5] Currently, catalytic hydrogenation is the most common method for removing acetylene from ethylene, necessitating high temperature, high pressure, and precious metal catalysts. 6 On the other hand, carbon dioxide separation from hydrocarbons relies on chemical absorption, which consumes large amounts of organic solvents. 7 These techniques suffer from high energy consumption and significant carbon emissions. 8 In this context, there is an urgent need to develop a simple, efficient, and energy-saving C2H4 purification technology.