Achieving Record CH Packing Density for Highly Efficient CH/CH Separation with a Metal-Organic Framework Prepared by a Scalable Synthesis in Water.

Adsorptive CH/CH separation using metal-organic frameworks (MOFs) has emerged as a promising technology for the removal of CH (acetylene) impurity (1 %) from CH (ethylene). The practical application of these materials involves the optimization of separation performance as well as development of scalable and green production protocols. Herein, we report the efficient CH/CH separation in a MOF, Cu(OH)INA (INA: isonicotinate) which achieves a record CH packing density of 351 mg cm at 0.01 bar through high affinity towards CH. DFT (density functional theory) calculations reveal the synergistic binding mechanism through pore confinement and the oxygen sites in pore wall. The weakly basic nature of binding sites leads to a relatively low heat of adsorption (Q) of approximately 36 kJ/mol, which is beneficial for material regeneration and thermal management. Furthermore, a scalable and environmentally friendly synthesis protocol with a high space-time yield of 544 kg m day has been developed without using any modulating agents. This material also demonstrates enduring separation performance for multiple cycles, maintaining its efficacy after exposure to water or air for three months.