Molecular-Sieving Separation of Methanol/Benzene Azeotrope by a Flexible Metal–Organic Framework
Mu‐Yang Zhou, Xuewen Zhang, Yi Heng, Zhi‐Shuo Wang, Dong‐Dong Zhou, Rui‐Biao Lin, Jie‐Peng Zhang, Xiao‐Ming Chen
Abstract
Separation of methanol/benzene azeotrope mixtures is very challenging not only by the conventional distillation technique but also by adsorbents. In this work, we design and synthesize a flexible Ca-based metal–organic framework MAF-58 consisting of cheap raw materials. MAF-58 shows selective methanol-induced pore-opening flexibility. Although the opened pores are large enough to accommodate benzene molecules, MAF-58 shows methanol/benzene molecular sieving with ultrahigh experimental selectivity, giving 5.1 mmol g –1 high-purity (99.99%+) methanol and 2.0 mmol g –1 high-purity (99.97%+) benzene in a single adsorption/desorption cycle. Computational simulations reveal that the preferentially adsorbed, coordinated methanol molecules act as the gating component to selectively block the diffusion of benzene, offering a new gating adsorption mechanism.