Li Shu-Yi, Xue Ying-Ying, Wang Jia-Wen, Li Hai-Peng, Lei Jiao, Lv Hong-Juan, Bu Xianhui, Zhang Peng, Wang Ying, Yuan Wen-Yu, Zhai Quan-Guo
Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry & Chemical Engineering, Shaanxi Normal University Xi'an Shaanxi 710062 China
Department of Chemistry and Biochemistry, California State University Long Beach California 90840 USA
Chem Sci. 2024 Oct 4;15(42):17547-55. doi: 10.1039/d4sc04387a.
Recovery of light alkanes from natural gas is of great significance in petrochemical production. Herein, a promising strategy utilizing two types of size-complementary aromatic ring-confined nanotraps (called bi-nanotraps here) is proposed to efficiently trap ethane (CH) and propane (CH) selectively at their respective sites. Two isostructural metal-organic frameworks (MOFs, SNNU-185/186), each containing bi-nanotraps decorated with six aromatic rings, are selected to demonstrate the feasibility of this method. The smaller nanotrap acts as adsorption sites tailored for CH while the larger one is optimized in size for CH. The separation is further facilitated by the large channels, which serve as mass transfer pathways. These advanced features give rise to multiple C-H⋯π interactions and size/shape-selective interaction sites, enabling SNNU-185/186 to achieve high CH adsorption enthalpy (43.5/48.8 kJ mol) and a very large thermodynamic interaction difference between CH and CH. Benefiting from the bi-nanotrap effect, SNNU-185/186 exhibits benchmark experimental natural gas upgrade performance with top-level CH productivity (6.85/6.10 mmol g), ultra-high purity and first-class capture capacity for CH (1.23/0.90 mmol g) and CH (2.33/2.15 mmol g).
从天然气中回收轻质烷烃在石油化工生产中具有重要意义。在此，提出了一种利用两种尺寸互补的芳香环限制纳米阱（在此称为双纳米阱）的有前景的策略，以在各自的位点高效且选择性地捕获乙烷（C₂H₆）和丙烷（C₃H₈）。选择了两种同构金属有机框架（MOFs，SNNU - 185/186），每种都含有装饰有六个芳香环的双纳米阱，以证明该方法的可行性。较小的纳米阱作为为C₂H₆量身定制的吸附位点，而较大的纳米阱在尺寸上针对C₃H₈进行了优化。大通道进一步促进了分离，其作为传质途径。这些先进特性产生了多种C - H⋯π相互作用和尺寸/形状选择性相互作用位点，使SNNU - 185/186能够实现高的C₂H₆吸附焓（43.5/48.8 kJ mol⁻¹）以及C₂H₆和C₃H₈之间非常大的热力学相互作用差异。受益于双纳米阱效应，SNNU - 185/186展现出具有基准水平的实验性天然气提质性能，具有顶级的C₂H₆生产率（6.85/6.10 mmol g⁻¹）、超高纯度以及一流的C₂H₆（1.23/0.90 mmol g⁻¹）和C₃H₈（2.•33/2.15 mmol g⁻¹）捕获能力。
