title: CD-MOF: A Versatile Separation Medium.
abstract: Porous metal-organic frameworks (MOFs) have been studied in the context of a wide variety of applications, particularly in relation to molecular storage and separation sciences. Recently, we reported a green, renewable framework material composed of γ-cyclodextrin (γ-CD) and alkali metal salts--namely, CD-MOF. This porous material has been shown to facilitate the separation of mixtures of alkylaromatic compounds, including the BTEX mixture (benzene, toluene, ethylbenzene, and the regioisomers of xylene), into their pure components, in both the liquid and gas phases, in an energy-efficient manner which could have implications for the petrochemical industry. Here, we report the ability of CD-MOF to separate a wide variety of mixtures, including ethylbenzene from styrene, haloaromatics, terpinenes, pinenes and other chiral compounds. CD-MOF retains saturated compounds to a greater extent than their unsaturated analogues. Also, the location of a double bond within a molecule influences its retention within the extended framework, as revealed in the case of the structural isomers of pinene and terpinine, where the isomers with exocyclic double bonds are more highly retained than those with endocyclic double bonds. The ability of CD-MOF to separate various mono- and disubstituted haloaromatic compounds appears to be controlled by both the size of the halogen substituents and the strength of the noncovalent bonding interactions between the analyte and the framework, an observation which has been confirmed by molecular simulations. Since CD-MOF is a homochiral framework, it is also able to resolve the enantiomers of chiral analytes, including those of limonene and 1-phenylethanol. These findings could lead to cheaper and easier-to-prepare stationary phases for HPLC separations when compared with other chiral stationary phases, such as CD-bonded silica particles.
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors.forename: Karel J
authors.initials: KJ
authors.lastname: Hartlieb
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.|Wolfson Northern Carbon Reduction Laboratories, School of Chemical Engineering and Advanced Materials, Newcastle University , Newcastle upon Tyne NE1 7RU, U.K.
authors.forename: James M
authors.initials: JM
authors.lastname: Holcroft
authors.affiliation: Department of Chemical & Biological Engineering, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors.forename: Peyman Z
authors.initials: PZ
authors.lastname: Moghadam
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors.forename: Nicolaas A
authors.initials: NA
authors.lastname: Vermeulen
authors.affiliation: Joint Center of Excellence in Integrated Nano-Systems, King Abdulaziz City for Science and Technology , P.O. Box 6086, Riyadh 11442, Saudi Arabia.
authors.forename: Mohammed M
authors.initials: MM
authors.lastname: Algaradah
authors.affiliation: Joint Center of Excellence in Integrated Nano-Systems, King Abdulaziz City for Science and Technology , P.O. Box 6086, Riyadh 11442, Saudi Arabia.
authors.forename: Majed S
authors.initials: MS
authors.lastname: Nassar
authors.affiliation: PanaceaNano, Inc. , 2265 East Foothill Boulevard, Pasadena, California 91107, United States.
authors.forename: Youssry Y
authors.initials: YY
authors.lastname: Botros
authors.affiliation: Department of Chemical & Biological Engineering, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors.forename: Randall Q
authors.initials: RQ
authors.lastname: Snurr
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors.forename: J Fraser
authors.initials: JF
authors.lastname: Stoddart