Highly Selective, High-Capacity Separation of o-Xylene from C 8 Aromatics by a Switching Adsorbent Layered Material

• Published in: Angewandte Chemie International Edition Vol. 58; no. 20; pp. 6630 - 6634
• Main Authors: Wang, Shi-Qiang, Mukherjee, Soumya, Patyk-Kaźmierczak, Ewa, Darwish, Shaza, Bajpai, Alankriti, Yang, Qing-Yuan, Zaworotko, Michael J
• Format: Journal Article
• Language: English
• Published: Germany 13.05.2019
• Subjects: square lattice coordination networks; physisorptive separation; C8 aromatics; nonporous layered materials; switching behavior
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201901198

Purification of the C aromatics (xylenes and ethylbenzene) is particularly challenging because of their similar physical properties. It is also relevant because of their industrial utility. Physisorptive separation of C aromatics has long been suggested as an energy efficient solution but no physisorbent has yet combined high selectivity (>5) with high adsorption capacity (>50 wt %). Now a counterintuitive approach to the adsorptive separation of o-xylene from other C aromatics involves the study of a known nonporous layered material, [Co(bipy) (NCS) ] (sql-1-Co-NCS), which can reversibly switch to C aromatics loaded phases with different switching pressures and kinetics, manifesting benchmark o-xylene selectivity (S ≈60) and high saturation capacity (>80 wt %). Structural insight into the observed selectivity and capacity is gained by analysis of the crystal structures of C aromatics loaded phases.