Fully inverse adsorption enables one-step high-purity C<sub>2</sub>H<sub>2</sub> separation from ternary C2 mixtures in a robust porous crystal.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41253810.
- Also identified by DOI 10.1038/s41467-025-65057-8 and PMC identifier 12627629.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Direct harvesting of electronic-grade acetylene (C<sub>2</sub>H<sub>2</sub>) from ternary C2 mixtures is a great challenge due to the ubiquitous adsorption preference of conventional porous materials (C<sub>2</sub>H<sub>2</sub> > ethylene (C<sub>2</sub>H<sub>4</sub>) > ethane (C<sub>2</sub>H<sub>6</sub>)). Here, we report a strategy to reverse this selectivity by leveraging ligand functionalization in porous crystals. Through the incorporation of trifluoromethyl/methyl groups into a pyrazole-carboxylate linker, we engineer a series of MOF-5 analogs. The optimal material, NTU-98, fully reverses the adsorption trend of C2 hydrocarbons (C<sub>2</sub>H<sub>6</sub> > C<sub>2</sub>H<sub>4</sub> > C<sub>2</sub>H<sub>2</sub>), enabling direct production of C<sub>2</sub>H<sub>2</sub> with >99.99% purity from ternary feeds at room temperature in one-step. Combined density functional theory calculations and gas-loaded crystallographic analyses unveil the molecular mechanism: methyl groups precisely positioned within the cages enhance host-guest interactions with C<sub>2</sub>H<sub>4</sub> and C<sub>2</sub>H<sub>6</sub>, while suppressing the binding affinity for C<sub>2</sub>H<sub>2</sub>. This work presents a porous crystal for direct C<sub>2</sub>H<sub>2</sub> purification from ternary feeds and a blueprint for designing microporous environments targeting challenging separations.