Abstract
Professors Myoung Soo Lah and Seung Kyu Min from the Department of Chemistry at UNIST, in collaboration with Professor Hyungphil Chun at Hanyang University ERICA Campus, announced the development of a novel porous material capable of high-purity separation of xylene isomers at room temperature. This breakthrough promises to significantly reduce energy consumption and process complexity in petrochemical refining.
Xylene, a key raw material used in plastic bottles, synthetic fibers, and fragrances, exists as three isomers-ortho-, meta-, and para-xylene-each with distinct applications. These isomers, along with ethylbenzene, are typically produced as a mixture in petrochemical processes, requiring energy-intensive separation steps under high temperature and pressure.
Figure 1. Schematic image, illustrating channel confinement via rigid cylindrical pillaring in a MOF framework enables molecular sieving through elliptical windows, offering a blueprint for ambient-condition xylene isomer separation.
The research team successfully developed a porous metal-organic framework (MOF) that selectively captures and separates these isomers under ambient conditions. Unlike conventional MOFs, which feature open channels on multiple sides, this innovative design has blocked side pores and open vertical channels. This structure was achieved by incorporating a large organic molecule called DABCO into a nickel-based framework. This configuration functions as a molecular sieve: the bent shape of ortho-xylene is effectively filtered out at the entry point, while the elongated para-xylene and ethylbenzene molecules can pass through and be adsorbed within the internal pores.
This specially designed MOF demonstrated up to 268 times higher selectivity for ortho-xylene compared to existing materials, with performance maintained over multiple reuse cycles. Such high selectivity at room temperature represents a significant advancement over traditional high-temperature separation methods.
Professor Lah explained, "Our new material can spontaneously separate specific xylene isomers at ambient conditions, overcoming the limitations of high-temperature, high-pressure processes." He further added, "This innovation could lead to more energy-efficient and environmentally friendly petrochemical separation techniques, contributing to sustainable industrial practices."
The research was conducted by Seonghwan Lee, Amitosh Sharma, and Jae Hyeok Lee, who served as first authors. Their findings have been published in the online version of Angewandte Chemie International Edition on July 18, where it was featured as a cover article. This study was supported by the Ministry of Science and ICT (MSIT) and the National Research Foundation of Korea (NRF).
Journal Reference
Seonghwan Lee, Amitosh Sharma, Jae Hyeok Lee, et al., "Highly Selective Adsorption of Para-Xylene, Ethylbenzene, and Explicit Exclusion of Ortho-Xylene from Xylene Isomers Using a Pillar-Layered MOF with Tuned Pore Channels," (2025).
