Reversed ethane/ethylene adsorption in a metal-organic framework introduction of oxygen.

Separation of ethane from ethylene is a very important but challenging process in the petrochemical industry. Finding an alternative method would reduce the energy needed to make 170 million tons of ethylene manufactured worldwide each year. Adsorptive separation using CH-selective porous materials to directly produce high-purity CH is more energy-efficient. We herein report the "reversed CH/CH adsorption" in a metal-organic framework Cr-BTC the introduction of oxygen on its open metal sites. The oxidized Cr-BTC(O) can bind CH over CH through the active Cr-superoxo sites, which was elucidated by the gas sorption isotherms and density functional theory calculations. This material thus exhibits a good performance for the separation of 50/50 CH/CH mixtures to produce 99.99% pure CH in a single separation operation.