Efficient Separation of Methanol‐to‐Olefins Products Using a Robust Polycatenated Hydrogen‐bonded Organic Framework

The methanol‐to‐olefins process produces mixtures of ethylene and propylene, driving demand for high‐performance separation materials. We present HOF‐ZJNU‐3, a hydrogen‐bonded organic framework built from an expanded BTB (4,4’,4’’‐benzene‐1,3,5‐triyl‐tribenzoate) linker, featuring the highest catenation degree observed in BTB‐based HOFs. This unique architecture confers good stability under solvent, pH, and thermal conditions. With optimally sized pores and aromatic‐rich surfaces, HOF‐ZJNU‐3 demonstrates excellent propylene/ethylene separation potential, outperforming its parent frameworks (HOF‐BTB and HOF‐BTB‐NH2) under ambient conditions. Notably, the material accomplishes single‐cycle purification of high‐purity ethylene (99.95%) and propylene (99.5%) from equimolar binary mixtures, achieving a record ethylene productivity of 3.22 mol kg‐1 among HOF adsorbents. This study not only establishes HOF‐ZJNU‐3 as a benchmark HOF material for MTO product separation but also advances the structural design of HOFs for industrial olefin purification.