Selectivity Separation of <i>Ortho</i>-Chlorotoluene Using Nonporous Adaptive Crystals of Hybrid[3]arene

Abstract

Ortho-chlorotoluene serves as a vital raw material in the petrochemical industries. However, due to alkylation and chlorination, ortho-chlorotoluene is often mixed with meta-chlorotoluene and para-chlorotoluene. The selective separation of ortho-chlorotoluene from chlorotoluene isomers is a crucial step in industrial production. However, owing to the close boiling points of chlorotoluene isomers, traditional separation methods demand a large amount of energy. Therefore, there is an urgent need to develop new methods to achieve the efficient separation of chlorotoluene isomers. Herein, we developed an adsorptive separation strategy to achieve the separation of ortho-chlorotoluene using nonporous adaptive crystals of hybrid[3]­arene H (Hα). Hα was proved to be highly effective in the separation of ortho-chlorotoluene from the binary or ternary mixture of chlorotoluene isomers. Single-crystal structure analysis and electrostatic potential maps indicated that the selectivity was derived from the stable host–guest structure between ortho-chlorotoluene and H. Besides, Hα exhibited high recyclability due to the reversible transformation between guest-free and guest-contained structures