Fluorinated Macrocycle for Adsorptive Separation and Chromatographic Separation of Toluene and Methylcyclohexane.

Achieving the adsorptive separation and chromatographic separation of industrially the important chemicals toluene and methylcyclohexane using the same material is a highly desirable goal. We have successfully accomplished this using a fluorinated macrocycle tetrafluoroterphen[3]arene (4FTP3), which was synthesized and used for gas chromatographic separation in our previous work. The macrocycle 4FTP3 permitted the adsorptive separation of toluene from a toluene/methylcyclohexane mixture (1 : 1, v/v) with a purity of 99.3 % in a single adsorption cycle. Additionally, the use of 4FTP3 as a gas chromatographic stationary phase permitted the high-resolution separation of a toluene/methylcyclohexane mixture, with a retention capacity decreasing in the order of: toluene>methylcyclohexane. Single-crystal structural analysis revealed that the C-H⋅⋅⋅F interactions between 4FTP3 and toluene resulted in an enhanced binding affinity, association enthalpy, and longer retention time for toluene. This macrocycle is of particular interest for use as a separation material due to its simultaneous adsorptive separation and gas chromatographic separation of toluene/methylcyclohexane. The present fluorinated macrocycle may therefore have roles to play in both analytical science and the chemical industry.
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