Hexafluorogermanate (GeFSIX) Anion-Functionalized Hybrid Ultramicroporous Materials for Efficiently Trapping Acetylene from Ethylene

Abstract

A trace amount of acetylene (C2H2, 1%) removal from ethylene/acetylene mixture is crucial for the production of polymer-grade ethylene (C2H4), which is a highly challenging task and currently is mainly realized via highly energy-intensive technologies. Herein, we first report the highly efficient trapping of C2H2 from C2H2/C2H4 mixtures using two hexafluorogermanate (GeF62–, GeFSIX) anion-functionalized hybrid ultramicroporous materials, GeFSIX-2-Cu-i and GeFSIX-14-Cu-i (also termed ZU-32 and ZU-33), as novel adsorbents. These GeFSIX materials exhibit high thermal stability and tunable pore structures and have a high density of electronegative GeF62– anions decorated on the pore surface. ZU-32 with an aperture size of 4.5 A exhibits preferential binding ability for C2H2 molecules and thus offers an excellent separation selectivity of 67 for the C2H2/C2H4 (1/99) mixture. ZU-33 with 4,4-azopyridine (azpy, 9.0 A) as an organic linker exhibits a contracted pore window size with pyridine ring tilting of ca. 30...