Highly selective separation of toluene and methylcyclohexane based on nonporous adaptive crystals of hybrid[3]arene†

Abstract

The efficient separation of toluene and methylcyclohexane is one of the biggest challenges in the field of chemical separation. Due to their closely matched boiling points, traditional distillation separation methods consume a lot of energy. Therefore, it is imperative to develop novel separation techniques to obtain toluene and methylcyclohexane with high purities. Herein, we develop an economical strategy for adsorptive separation based on nonporous adaptive crystals of hybrid[3]arene H (Hα). Hα selectively separate toluene from the mixture of toluene and methylcyclohexane (v : v = 1 : 1) with a purity of 100% via the vapor–solid adsorption and a purity of 98.98% via the liquid–solid adsorption. The selectivity arises from the stability of the new crystal structure after the capture of the preferred guest, toluene, by Hα. The reversible transition between guest-free and guest-loaded structures endows Hα with excellent recyclability.