Hydrogen-Bonded Organic Framework for Fluorescence-Guided Toluene/Methylcyclohexane Separation

The efficient separation of a toluene (Tol) and methylcyclohexane
(MCH) mixture is a valuable but challenging process in industrial
production. Hydrogen-bonded organic frameworks (HOFs) stand out among
many porous materials and have emerged as promising porous materials
for liquid separation. In this study, a tetradentate thieno[3,2-b]thiophene derivative (CN4TT) was prepared,
and a HOF (HOF-TT-1) was synthesized via a solvothermal
method. After heating to remove the solvent from the pores (HOF-TT-1a), its fluorescence remarkably changed from its original
cyan to blue. The material was utilized to separate a mixture of Tol
and MCH, and it was observed to have higher toluene adsorption and
to revert to cyan fluorescence after adsorption. Additionally, the
material exhibited thermal and acid–base stability, and the
adsorption efficiency remained above 89% after five adsorption cycles,
demonstrating a strong regenerative ability.