Metal-Organic Frameworks for Highly Selective Separation of Xylene Isomers and Single-Crystal X-ray Study of Aromatic Guest-Host Inclusion Compounds

Aleksandr A Sapianik; Evgeny R Dudko; Konstantin A Kovalenko; Marina O Barsukova; Denis G Samsonenko; Danil N Dybtsev; Vladimir P Fedin

doi:10.1021/acsami.1c02812

Metal-Organic Frameworks for Highly Selective Separation of Xylene Isomers and Single-Crystal X-ray Study of Aromatic Guest-Host Inclusion Compounds

ACS Appl Mater Interfaces. 2021 Mar 31;13(12):14768-14777. doi: 10.1021/acsami.1c02812. Epub 2021 Mar 17.

Authors

Aleksandr A Sapianik^{1

2}, Evgeny R Dudko^{2

3}, Konstantin A Kovalenko², Marina O Barsukova^{1

2}, Denis G Samsonenko², Danil N Dybtsev², Vladimir P Fedin²

Affiliations

¹ Functional Materials Design, Discovery and Development Research Group (FMD3), Advanced Membranes and Porous Materials Center (AMPM), Division of Physical Sciences and Engineering (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
² Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia.
³ Novosibirsk State University, Novosibirsk 630090, Russia.

PMID: 33729772
DOI: 10.1021/acsami.1c02812

Abstract

Separation of hydrocarbon molecules, such as benzene/cyclohexane and o-xylene/m-xylene/p-xylene, is relevant due to their widespread application as chemical feedstock but challenging because of their similar boiling points and close molecular sizes. Physisorption separation could offer an energy-efficient solution to this problem, but the design and synthesis of sorbents that exhibit high selectivity for one of the hydrocarbons remain a largely unmet challenge. Herein, we report a new heterometallic MOF with a unique tortuous shape of channels decorated with aromatic sorption sites [Li₂Zn₂(bpy)(ndc)₃] (NIIC-30(Ph), bpy = 4,4'-bipyridine, ndc^2- = naphthalene-1,4-dicarboxylate) and study of its benzene/cyclohexane and xylene vapor and liquid separation. For an equimolar benzene/cyclohexane mixture, it is possible to achieve a 10-fold excess of benzene in the adsorbed phase. In the case of xylenes, microporous framework NIIC-30(Ph) demonstrates outstanding selective sorption properties and becomes a new benchmark for m-/o-xylene separation. In addition, NIIC-30(Ph) is stable enough to carry out at least three separation cycles of benzene/cyclohexane mixtures or ternary o-xylene/m-xylene/p-xylene mixtures both in the liquid and in the vapor phase. Insights into the performance of NIIC-30(Ph) are gained from X-ray structural studies of each aromatic guest inclusion compound.

Keywords: benzene; heterometallic; metal−organic frameworks; preorganized complexes; separation; sorption; xylenes.