Preparation and application of novel MIL-101(Cr) composite in liquid chromatographic separation of aromatic compounds: experimental and computational insights.

Abstract

A novel composite material of SiO2@dSiO2@MIL-101(Cr) was synthesized via SiO2@dSiO2 as the core and MIL-101(Cr) as the shell to separate aromatic compounds. The laboratory prepared column gave rise to the baseline separation of xylene, dichlorobenzene isomers, phthalate esters, nitrobenzene, and acetophenone with high column efficiency (e.g., 109,050 platesm-1 for methyl phthalate) and good precision (e.g., 0.02-0.05%, 0.24-0.34%, 0.14-0.18%, and 0.11-0.13% corresponding to the relative standard deviation of retention time, peak area, peak height, and half peak width for xylene isomers, respectively). The calculation of thermodynamic parameters demonstrated that the separation of o-xylene, nitrobenzene, acetophenone, and p-dichlorobenzene was controlled by positive ∆H and ∆S. Although the separation of aromatic compounds by aMOF packed column has been reported in many studies, the knowledge regarding their separation mechanism at atomic level is still very limited. In this study, we integrate fully atomistic molecular dynamics simulation and binding free energy calculation to investigate the separation mechanism of aromatic compounds by MIL-101(Cr). The investigation provides a base forseparation ofmoreand other compounds in the future. Graphical abstract.