Shape-Recognition in an Al-MOF Enables High C₃F₆ Adsorption and Size-Sieving Separation of C₃F₆/C₃F₈

Area of Science:

• Materials Science
• Chemical Engineering
• Separation Science

Background:

• Purification of perfluoropropane (C3F8) requires selective removal of perfluoropropylene (C3F6).
• Similar physicochemical properties of C3F6 and C3F8 pose significant separation challenges.
• Existing methods struggle with efficient and low-pressure separation.

Purpose of the Study:

• To develop a novel material for the selective separation of C3F6 from C3F8.
• To investigate the adsorption properties and separation capabilities of a new Al-based MOF, HIAM-344.
• To achieve high-purity C3F8 production through efficient C3F6 removal.

Main Methods:

• Synthesis and characterization of a rigid Al-based Metal-Organic Framework (MOF), HIAM-344.
• Utilizing HIAM-344's nitrate-regulated narrow pore windows for molecular sieving.
• Performing dynamic breakthrough experiments for gas separation.
• Conducting computational studies to understand separation mechanisms.

Main Results:

• HIAM-344 demonstrated a record-high C3F6 uptake of 78.8 cm³ g⁻¹ at 1 bar and maintained 59.2 cm³ g⁻¹ at 0.01 bar.
• Complete separation of C3F6 and C3F8 was achieved in dynamic breakthrough experiments.
• Production of electronic-grade C3F8 (>99.999%) was directly enabled by the material's performance.
• Computational studies confirmed synergistic size/shape recognition and favorable adsorbate-adsorbent interactions.

Conclusions:

• HIAM-344 exhibits exceptional performance for selective C3F6/C3F8 separation via molecular sieving.
• The MOF's unique pore structure and chemistry facilitate high adsorption capacity and efficient separation at low pressures.
• This material offers a promising solution for producing high-purity electronic-grade C3F8.