Highly Porous Scandium(III) Tetrafluoroisophthalate Framework for Adsorptive Separation of Light Alkanes

The separation of light alkanes is one of the most important tasks for modern industry due to the widespread use of ethane and propane as chemical feedstocks. Their extraction from natural gas is a challenging task and is now carried out by cryogenic distillation at a limited number of plants around the world. The development of new materials for adsorption separation is therefore important. Among the different types of adsorbents, metal-organic frameworks (MOFs) are one of the most interesting due to their infinite design possibilities. Here we present a highly porous perfluorinated MOF [Sc(OH)(1,3-tFbdc)] (1,1,3-tFbdc^2-─1,3-C₆F₄(COO)₂^2- tetrafluoroisophthalate linker) with a BET surface area greater than 1000 m·g^-1 and its ability to separate light alkanes was investigated. The ability of 1 to separate light hydrocarbons at 0 and 25 °C is demonstrated by IAST calculation of selectivity factors as well as by dynamic breakthrough experiments. The role of fluorine substituents within the organic linker of MOF 1 in gas adsorption is revealed by quantum chemical calculations.