Synchronous conversion of lignocellulosic polysaccharides to levulinic acid with synergic bifunctional catalysts in a biphasic cosolvent system

Synchronous conversion of lignocellulosic polysaccharides to a high-value-added chemical (levulinic acid, LA) using various Bronsted-Lewis acids as bifunctional catalysts in a biphasic cosolvent system has been investigated. The results indicate that the coupling of Amberlyst 15 and Al-2(SO4)(3) as a bifunctional catalyst has a higher positive synergic influence on the synchronous conversion of cellulose and hemicellulose to LA than other mixed catalysts. The synergic effect of a Bronsted-Lewis acid was measured using a synergy factor; the Amberlyst 15-Al-2(SO4)(3) bifunctional catalyst showed the strongest synergic catalytic activity with a synergy factor of 1.90. The biphasic cosolvent combining water with dimethoxymethane promotes the transformation of furfural into hydroxymethylfurfural and facilitates the selectivity of LA. The results also demonstrated that the water-dimethoxymethane biphasic cosolvent is suitable for the synchronous conversion of hemicellulose and cellulose into LA with high yield (52.49 %). This study provides insights for the possible synergistically transformed mechanism of lignocellulosic polysaccharides according to the conversion of intermediates and products. This synchronous conversion of biomass with a synergistic system has great promise for preparing high-value-added chemicals from biomass.