Separate xylene isomers with less energy

Xylene isomers are usually derived from the catalytic reforming of crude oil, and require costly methods to separate them from each other, including distillation, fractional crystallization and adsorption in high-temperature and high-pressure environments. “The separation of xylene’s isomers requires much energy and is a difficult process due to the isomers’ overlapping physiochemical properties,” says Abdul-Hamid Emwas, staff scientist in nuclear magnetic resonance (NMR) from the Imaging and Characterization Core Lab (IAC) at the King Abdullah University of Science and Technology (KAUST; Thuwal, Saudi Arabia; www.kaust.edu.sa). “These include identical molecular weights, close boiling points and similar structures.” KAUST associate professor Niveen Khashab and her research group recently teamed up with IAC and an international group of scientists to find a new and less energy-consuming method to separate and purify the isomers for the petrochemical industry. Their work is described in a recent issue of the journal Chem. To separate the isomers, the research team took advantage of the properties of cucurbiturils, which are organic macrocyclic molecules made of glycoluril monomers linked by methylene bridges. They are…