Selective Acetylene Adsorption within an Imino Functionalized Nanocage-Based Metal-Organic Framework.

The removal of CH4 and CO2 from C2H2 streams is very challenging in chemical industry. Herein, a robust metal-organic framework, Cu-CPAH, was designed and synthesized by hydrothermal method. With abundant active sites in the framework, Cu-CPAH exhibits remarkably selective adsorption of C2H2 over CH4 and CO2. Breakthrough experiments show that Cu-CPAH can be used as solid adsorbent for high performance purification of C2H2 from a equimolar mixture of C2H2/CO2 or C2H2/CO2/CH4 at room temperature. Discrete Fourier transform (DFT) simulations were also excuted to provide a clear visualization on the preferential stronger interaction of C2H2 with various active sites than CO2 and CH4, demonstrating for the first time the contribution of imino functional groups in the cage which play a more critical role in the preferential fixation of C2H2 than CO2.