Iron-Based Metal–Organic Framework with Hydrophobic Quadrilateral Channels for Highly Selective Separation of Hexane Isomers

Abstract

A novel iron-based microporous metal-organic framework built of trinuclear iron clusters [Fe(μ-O)(COO)] and 2,2-bis(4-carboxyphenyl)-hexafluoropropane (6FDCA) has been prepared by solvothermal synthesis. It exhibits excellent chemical stability and strong hydrophobic character. More importantly, this material is capable of separating hexane isomers with good separation performance on the basis of a kinetically controlled process, making it a promising candidate for improving the research octane number of gasoline.

One-of-a-kind: a microporous metal–organic framework capable of adsorptive separation of linear, mono- and di-branched alkane isomers via temperature- and adsorbate-dependent molecular sieving

“…Y-fum and ZIF-8 are two representative MOFs that show excellent separation of linear and monobranched alkanes, 7,16 but like zeolite 5A, they cannot separate monobrached and dibranched isomers. Adsorbents that show dicrimination between mono-and di-branched alkanes include zeolite BETA, 17 MFI, 18 Zn2(HBDC)2(dmtrz)2, 19 Fe2(BDP)3, 15 and Fe3O(6FDCA)3, 20 to name a few, however, the separation by these materials is achieved by moderate differences in either adsorption affinity or rates, which leads to relatively low selectivity and efficiency. In this work we demonstrate, for the first time, that the separation of monobranched and dibranched alkane isomers can be achieved by a microporous MOF, Ca(H2tcpb), through selective molecular exclusion.…”

Advances in Organic Solvent Nanofiltration Rely on Physical Chemistry and Polymer Chemistry

“…Recently, a new MOF with hydrophobic quadrilateral channels was synthesized via a solvothermal process from [Fe 3 (μ 3 -O)(COO) 6 ] and 2,2-bis(4-carboxyphenyl)-hexafluoropropane (6FDA) and tested for separation of hexane isomers (Lv et al, 2018 ). The successful separation of n-hexane from its branched isomers relies essentially on solubility-selectivity, as linear n-hexane can be selectively sorbed by the [Fe 3 (μ 3 -O)(COO) 6 ]-6FDA MOF, while sorption of branched isomers is sterically hindered.…”

Moisture stability of ethane‐selective Ni(II), Fe(III), Zr(IV)‐based metal–organic frameworks

“…All correlation coefficients ( R 2 ) reach 0.9999, indicating that DSLF model is capable of describing all measured ethylene and ethane adsorption isotherms on Zr‐bptc. IAST, as widely used methods for predicting gas mixture adsorption selectivity, has been used to calculated ethane/ethylene adsorption selectivities. Selectivity ( S ) is calculated with Equation : where x i and y i separately are the volume fractions in the adsorbent and the gas mixture at a pressure.…”

“…To develop moisture stable MOFs, researchers have been trying to find out the factors that affect the water vapor stability of MOFs . It was widely proposed that the hydrophobicity of MOFs was an important factor affecting moisture stability of MOFs . First, pore hydrophobicity of MOFs can increase moisture stability by decreasing the adsorbed amount of water vapor into channels.…”