Green hydrolysis of corncob cellulose into 5-hydroxymethylfurfural using hydrophobic imidazole ionic liquids with a recyclable, magnetic metalloporphyrin catalyst

Abstract

Ionic liquids (ILs) with catalysts have been widely investigated in the production of 5-hydroxymethylfurfural (5-HMF) from biomass, in particular those which are high in cellulose. In this study, a series of hydrophobic imidazolium ionic liquids and magnetic-chitosan metallo-porphyrin particles (MCMP-M) were designed and their abilities to convert 5-hydroxymethylfurfural (5-HMF) and total reducing sugars (TRS) from the corncob were evaluated. The results showed that [moMIM][PF6] and MCMP-Al were suitable solvents and both the catalysts were effective for the 5-HMF and TRS conversion (52.47 and 31.06, respectively). The mixed catalysts (MCMP-Al, Cr and Mg) coupled with [moMIM][PF6] could increase the conversion yield of 5-HMF and TRS (66.58% and 43.68% in 50min, respectively) with infrared radiation heating during distillation under reduced pressure for a short time (50min). More importantly, the products could be separately recovered through the aqueous phase and the ILs and catalysts could be reused up to 40 times despite the slight loss of its catalytic activity. Moreover, the catalyst system also could be used for other carbon sources to produce the 5-HMF.