Arraying Shape-Persistent Molecular Alkynyl Trap into Highly Porous and Robust Zirconium Metal-Organic Framework for...

Area of Science:

• Materials Science
• Chemical Engineering
• Separation Science

Background:

• Adsorptive separation of propyne/propylene (C3H4/C3H6) is crucial for energy-efficient production of polymer-grade C3H6.
• Current adsorbents, like ultramicroporous metal-organic frameworks (MOFs), have limitations in C3H4 uptake capacity and adsorption enthalpy.
• Existing MOFs often feature narrow channels or inorganic anion pillars, hindering optimal separation performance.

Purpose of the Study:

• To develop a highly porous and robust zirconium metal-organic framework (MOF) for efficient C3H4/C3H6 separation.
• To investigate the structure-property relationships governing selective C3H4 adsorption.
• To demonstrate the practical application of the novel MOF in producing polymer-grade C3H6.

Main Methods:

• Synthesis and characterization of a novel zirconium MOF, SJTU-520, incorporating cyclotetrabenzoin-derived molecular arrays.
• Adsorption isotherm measurements to quantify C3H4 and C3H6 uptake capacities and selectivity.
• Breakthrough experiments to validate separation performance under various conditions.
• Computational simulations to elucidate the mechanism of selective C3H4 adsorption.

Main Results:

• SJTU-520 exhibits a high surface area (3650 m²/g) and incorporates shape-persistent molecular arrays for selective C3H4 entrapment.
• Achieved record high C3H4/C3H6 uptake ratio and efficient separation at ambient conditions (1 bar, 298 K).
• Demonstrated a 6.1-fold increase in C3H4 uptake compared to related materials without compromising selectivity.
• Successful separation of polymer-grade C3H6 from a 10/90 C3H4/C3H6 mixture with excellent recyclability.

Conclusions:

• SJTU-520 represents a significant advancement in MOF-based adsorbents for C3H4/C3H6 separation.
• The reticulation of intrinsically functional organic scaffolds offers a powerful strategy for designing bespoke porous materials.
• This work paves the way for more energy-efficient industrial separation processes, particularly for polymer production.