Influence of 2-ethylimidazole linker-doping in ZIF-8 crystals on intracrystalline self-diffusion of gas molecules by high field diffusion NMR

Pulsed field gradient (PFG) NMR at high magnetic is used to study molecular self-diffusion of ethylene, ethane, and propylene in a 2-ethylimidazole (eIm) linker-doped ZIF-8. These eIm-doped materials were synthesized by incorporating increasing fractions the non-native eIm linker, which substitutes native 2-methylimidazole linker ZIF-8 framework. Self-diffusion three hydrocarbon gases was measured limits low loading pressure six different ZIFs with framework between 0 22.2%. It found that elm substitution shows tendency gas intracrystalline diffusivities, particularly for larger sorbates pressures. also observed ethylene/ethane diffusion selectivity, viz. ratio ethylene ethane does not show any dependence, within uncertainty, on extent substitution. Based these results it concluded likely introduce small changes microstructure result slightly pore aperture sizes, but smaller flexibility comparison parent material.