Highly Efficient Propyne/Propylene Separation in a "Flexible-Robust" and Hydrolytically Stable Cu(II)-MOF

Area of Science:

• Materials Science
• Chemical Engineering
• Adsorption Science

Background:

• Propyne/propylene separation is crucial in petrochemicals but difficult due to similar properties.
• Metal-organic frameworks (MOFs) are effective adsorbents for light hydrocarbon separations.
• Interpenetrated MOFs with "flexible-robust" characteristics offer enhanced selectivity and uptake.

Purpose of the Study:

• To develop novel hydrolytically stable, interpenetrated MOFs for propyne/propylene separation.
• To investigate the "flexible-robust" behavior of these MOFs for selective gas adsorption.
• To evaluate their performance in propyne/propylene separation via adsorption and breakthrough experiments.

Main Methods:

• Synthesis of two interpenetrated MOFs, BUT-308 and BUT-309.
• Gas adsorption measurements to determine adsorption isotherms and pore behavior.
• Column breakthrough experiments to assess separation efficiency of propyne/propylene mixtures.

Main Results:

• BUT-309 demonstrated "flexible-robust" adsorbent behavior with distinct adsorption isotherms for propyne over propylene.
• Guest-dependent pore-opening was observed in BUT-309, crucial for selective C3H4/C3H6 separation.
• BUT-309 efficiently removed propyne from a binary gas mixture, with optimal performance at lower temperatures.

Conclusions:

• BUT-308 and BUT-309 are stable, interpenetrated MOFs with significant propyne/propylene separation potential.
• BUT-309 exemplifies a "flexible-robust" MOF, showcasing guest-induced pore dynamics for selective adsorption.
• This study highlights the utility of "flexible-robust" MOFs for challenging light hydrocarbon separations.