Efficient Production of Furfural from Corncob by an Integrated Mineral-Organic-Lewis Acid Catalytic Process

An M-O-L acid (mineral acid, organic acid, and Lewis acid)-catalyzed integrated process for furfural production from corncob was proposed to improve corncob conversion and furfural selectivity. First, the co-catalysts of sulfuric acid and acetic acid were investigated for their impact on furfural production. Sulfuric acid as a pretreatment catalyst was mixed with corncob before the experiment. Acetic acid, which is a byproduct of hemicellulose hydrolysis, was fed together with steam. The results showed that the cooperation of sulfuric acid and acetic acid decreased the total acid consumption dramatically. FeCl3·6H2O was also investigated as a co-catalyst in an effort to enhance the conversion of xylose to furfural and decrease furfural degradation. The integrated catalytic process achieved the highest furfural yield of 68.04% through the use of M-O-L acid under a reaction temperature of 180°C, 3v% acetic acid, 4.0 wt.% sulfuric acid of 0.6 mL/g liquid to solid ratio, and 5 g FeCl3·6H2O per 100 g of biomass.