Metal-organic frameworks based isopentane nano-trap for molecular screening of isopentane from tetramethylsilane

Abstract

Tetramethylsilane (TMS) plays the crucial role in high-quality silicon carbide films, semiconductors, and low dielectric materials. However, the production of high pure TMS needs to remove isopentane, a byproduct with a nearly boiling point from TMS, consuming a large amount of energy in traditional distillation processes. Herein, a series of ultramicroporous MOFs, [M₃(HCOO)₆] (M = Co, Mg, Ni), featuring the synergy of nano-traps and molecular sieving effect, is synthesized to achieve efficient separation of TMS/isopentane. Co₃(HCOO)₆ exhibits distinct adsorption preferences among these MOFs, showing high isopentane uptake (2.72 mmol·g⁻¹) but limited TMS adsorption (0.33 mmol·g⁻¹) at 308 K and 60 kPa. Remarkably, it achieves a high-purity TMS (>99.999 %) productivity of 0.348 kg·kg⁻¹, demonstrating both exceptional adsorption capacity and unprecedented TMS/isopentane selectivity. Co₃(HCOO)₆ is further processed into pellets using polyether sulfone (PES) as a binder. Remarkably, Co₃(HCOO)₆@5%PES retains a high isopentane uptake of 2.59 mmol·g⁻¹, while maintaining a high-purity TMS (99.9993 %) productivity of 0.279 kg·kg⁻¹. The result demonstrates that the separation efficiencies remain comparable to powder, highlighting the promising prospects of composite adsorbents for practical applications