Science · Science, 2016
Telling propylene from propane
A fixed pore opening that takes up propylene and turns propane away.
Schematic of the outcome reported for KAUST-7 (NbOFFIVE-1-Ni) in laboratory mixed-gas adsorption at atmospheric pressure. Not to scale; not the crystal structure.
The question
Can a pore opening be fixed so precisely that two near-identical molecules are treated differently?
What was done
A fluorinated framework in which Ni(II)–pyrazine square-grid layers are bridged by (NbOF5)2− pillars. The bulkier pillars hinder the previously free-rotating pyrazine groups, which delimits the pore system and sets its maximum opening.
What the paper reports
The restricted window led to selective molecular exclusion of propane from propylene at atmospheric pressure, shown by repeated cycles of mixed-gas adsorption and by calorimetric studies.
What remains open
These are laboratory results on a crystalline adsorbent. Shaping the material, keeping it stable under real feeds and showing a gain at process scale are separate steps; no energy saving is claimed.
- Paper
- Cadiau, A.; Adil, K.; Bhatt, P. M.; Belmabkhout, Y.; Eddaoudi, M. A metal-organic framework-based splitter for separating propylene from propane. Science 353, 137–140 (2016).
- Credited
- Amandine Cadiau, Karim Adil, Prashant M. Bhatt, Youssef Belmabkhout and Mohamed Eddaoudi (KAUST).
- Link
- doi.org/10.1126/science.aaf6323