Selective Separation of Methylfuran and Dimethylfuran by Nonporous Adaptive Crystals of Pillararenes.

The separation of 2-methylfuran () and 2,5-dimethylfuran () mixtures is very important in the chemical industry. Herein, we offer a novel strategy for the separation of and using nonporous adaptive crystals (NACs) of perethylated pillar[5]arene (), perethylated pillar[6]arene (), perbromoethylated pillar[5]arene (), and perbromoethylated pillar[6]arene (). We find that the crystals of and show remarkable selectivities for in a 50:50 (/) : mixture vapor, yielding purities of 94.0 and 96.3%, respectively. Single-crystal structures reveal that these different selectivities come from the different thermodynamic stabilities and binding modes of the host-guest complexes. Cycling experiments demonstrate that these crystals can be reused more than five cycles without loss of performance.