Cost-Effective Scalable Production of Ultra-Stable Alkyl MOF Featuring Single-Molecule C3H6 Trap for Record Capture of Trace C3H6 from C2H4.

Abstract

Highly efficient capture of trace C3H6 from C2H4 by physisorbents remains an enormous challenge to combine top-rank separation performance with excellent stability and economical scalability. We, herein, built a single-molecule C3H6 trap that bears an opposite series of oxygen and dense alkyl groups distributed in an ultramicroporous [Al(OH)(trans-CDC)] (Al-CDC, trans-H2CDC = trans-1,4-cyclohexanedicarboxylic acid). The ultra-stable trap with well-matched pore size and pore chemistry enables a record uptake (40.8 cm3(STP) g-1) at ultralow concentration, Henry coefficient (12685.5 cm3(STP) g-1 bar-1), initial adsorption heat difference (27.2 kJ mol-1), adsorption kinetic (0.49 min-1) and kinetic selectivity (3.1) for C3H6 with one of the highest initial C3H6 adsorption heats (50.5 kJ mol-1) and selectivity (16.3), establishing a novel benchmark for capture of trace C3H6. The C3H6 adsorption mechanism is deciphered to be thermodynamically driven owing to the synergism of multiple hydrogen-bonding and van der Waals (vdW) forces. Breakthrough tests validate that Al-CDC owns a record C2H4 productivity (≥99.999%) of 410.5 cm3(STP) g-1 for trace C3H6 capture with excellent reproducibility. The cost-effective scalable production with the cheapest cost (508.9 $ kg-1) and highest space-time yield (4564.8 kg m-3 day-1) and shaping of Al-CDC is realized with unaffected structural property and capture performance.