The Origin of p-Xylene Selectivity in a DABCO Pillar-Layered Metal–Organic Framework: A Combined Experimental and Computational Investigation

We report high experimental p -xylene ( p X) selectivity in a pillar-layered metal–organic framework, DUT-8(Cu). Vapor- and liquid-phase adsorption experiments were carried out to confirm high p X selectivity and large p X uptakes in DUT-8(Cu). Grand canonical Monte Carlo simulation results show that the presence of DABCO ligands allows for the packing of p X molecules and is responsible for the p X selective nature of the material. The simulation also suggests that the presence of isooctane solvents in the liquid-phase experiments plays an essential role by lowering the adsorption of other xylene isomers, and leads to increased p X selectivity in the liquid-phase as compared to the vapor phase. Density functional theory simulations show that the preferential arrangement is due to the preferential adsorption of p X on the DABCO ligand and the preferential adsorption of isooctane over other xylene isomers.