Transformation of glycerol and CO2 to glycerol carbonate over ionic liquids-composite catalysts: Activity, stability, and effect of Li/Al metal oxide

Abstract

The direct conversion of glycerol and carbon dioxide (CO2) into glycerol carbonate (GC) provides a green pathway for utilizing both the waste glycerol and CO2. However, this reaction is hampered by low CO2 absorbency and H2O generation. Currently, high pressure and H2O trapping agents are employed to elucidate these problems. Our objective is to design a spongy metal oxide/ionic liquids (ILs) blended composite that can solve both limitations under moderate conditions. We created a glycol-modified biphasic cation with various anions aided ILs in combination with electrospin Li/Al nanofibers-500 (LANS-500). It achieved 98.40 % selectivity and 11.45 mmol g−1 cat., GC yield in 6 h at 4 MPa CO2 pressure, 140 °C, and 1.10 g catalyst. Furthermore, even after numerous recyclings, the catalyst yield or selectivity remain unaffected. Also, the LANS-500 catalyst has a porous nature which results in the formation of a strong “adduct” with CO2, as shown by Bode plot, FT-IR, and TGA analysis. ILs, conversely, are acidic, excellent thermal stability, low vapor pressure, and less viscosity. As a result, LANS-500 may be easily incorporated into ILs to produce a highly permeable network with high ratios of surface to volume to create a coordination structure that can absorb more CO2.