Hydrocarbon Recovery Using Ultra-Microporous Fluorinated MOF Platform Structure Properties Relationships for C2H2/C2H4 and C4 Olefins Separation Separations

In this work, the reticular chemistry approach was implemented on a very stable ultra-microporous fluorinated MFFIVE-1-Ni MOFs to unveil the effect of subtle changes of the structure-employment of different fluorinated inorganic block on the adsorption of C₂H₂, C₂H₄ and C₄ olefins. A series of variable temperature single C₂H₂, C₂H₄and C₄ adsorption isotherms and mixed gas adsorption column breakthrough experiments for different C₂H₂/C₂H₄and C₄ isomers gas pair systems were carried out on the two isoreticular NbOFFIVE-1-Ni and AlFFIVE-1-Ni, containing respectively [NbOF₅]^2- and [AlF₅]^2- inorganic building blocks. The introduction of potential open metal site in a very confined pores led to favoring interaction of C₂H₂ and C₂H₄ but lowering the interaction with CO₂, which resulted in enhancement of C₂H₂/C₂H₄ selectivity at low C₂H₂ concentration but a decrease in CO₂/C₂₊selectivity. The comparison of the C₂H₂/C₂H₄ and C₄ olefins separation performances with the structures of the MFFIVE-1-Ni MOFs provides useful information to shed light on the relationship between the structural features of this MOF platform and C₂H₂/C₂H₄ and C₄ olefins separation properties.