Synthesis and characterization of porous microspherical ionic liquid carbon cryogel catalyst for ethyl levulinate production

Abstract

A new type of carbon cryogel was synthesized from ionic liquid, a green solvent, and furfural mixtures. Initially, the gel, formed via sol-gel polycondensation reaction, was freeze-dried, calcined and denoted as CCIL. The effect of furfural to IL (F/IL) ratio, water to IL (W/IL) ratio and sulfuric acid loading on the synthesis of gel was investigated. In addition, the effect of calcination temperature and time were also studied for CCIL preparation. The physical and chemical properties were evaluated with nitrogen physisorption, temperature programmed desorption of ammonia (NH 3 -TPD), and thermogravimetric analyzer (TGA). Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy with energy dispersive X-ray spectrometry (FESEM-EDX), CHNS analysis, total organic carbon (TOC) and nuclear magnetic resonance spectroscopy (NMR) results were also analyzed. Catalytic testing, conducted to evaluate the performance of CCIL in esterification of levulinic acid with ethanol, inferred large total surface area and high acidity corroborated with good activity. The selected CCIL registered ethyl levulinate yield of 66.9 mol%. The experimental results demonstrated the catalyst, derived from new feedstocks, is a potential solid acid catalyst for biomass conversion.