Benchmark selectivity p-xylene separation by a non-porous molecular solid through liquid or vapor extraction

摘要

Solid–liquid separation of similarly sized organic molecules utilizing sorbents offers the potential for new energy-efficient approaches to a number of important industrial separations such as xylenes (C8) separations. Research on selective C8 sorption has tended to focus upon rigid porous materials such as zeolites and MOFs but has revealed generally weak selectivity that is inconsistent across the range of C8 molecules. Nevertheless, there are a few recent examples of non-porous molecular materials that exhibit relatively high selectivity for p -xylene ( p X) from p X/ o X, approaching that of the current benchmark p X sorbent, the zeolite H/ZSM-5. Herein, we report that a L-shaped Ag( I ) complex, Ag L ClO _(4) ( M ), which crystallizes as a non-porous molecular solid material, offering exceptional performance for p X selectivity across the range of C8 isomers with liquid extraction selectivity values of 24.0, 10.4 and 6.2 vs. o X, e B and m X, respectively. The p X selectivities over o X and e B are among the highest yet reported. Moreover, M also exhibits strong vapor extraction selectivity and can be regenerated by exposure to vacuum drying.