A Series of new Urea‐MOFs Obtained via Post‐synthetic Modification of NH2‐MIL‐101(Cr): SO2, CO2 and H2O Sorption

Abstract

AbstractThe amino group in the MOF NH2‐MIL‐101(Cr) was post‐synthetically converted into urea‐groups partially using either ethyl isocyanatoacetate, furfuryl isocyanate, p‐toluenesulfonyl isocyanate or 3‐(triethoxysilyl)propyl isocyanate in acetonitrile. The derived four novel urea‐MOFs exhibit the expected lower BET surface areas and pore volumes than MIL‐101(Cr) and NH2‐MIL‐101(Cr) MOFs but the partially p‐toluenesulfonyl‐urea‐modified MOF exhibits an outstanding SO2 adsorption capacity of 823 cm3 g−1 (corresponding to 36.7 mmol g−1 or 70 wt.% at T=0 °C and 0.9 bar), which is the second highest SO2 uptake of any known material today – surprisingly even better than for highly porous MIL‐101(Cr) with an uptake of 645 cm3 g−1 SO2 under the same conditions. The high uptake is linked to the favorable dipole interactions of SO2 with the sulfonyl group of the p‐toluenesulfonyl‐modified MOF.