Catalytic hydrolysis of cellulose to total reducing sugars with superior recyclable magnetic multifunctional MCMB-based solid acid as a catalyst

BACKGROUND Effective cellulose hydrolysis has a huge potential for producing high value-added biomass-based platform chemicals, such as glucose, hydroxymethylfurfural, levulinic acid, and total reducing sugars (TRS). Particularly, a magnetic multifunctional solid acid catalyst (Fe3O4/Cl-MCMB-SO3H) was synthesized by loading the active groups on the magnetic mesocarbon microbead (MCMB) derived from the co-calcination of coal tar pitch and ferroferric oxide, which was applied as a catalyst in the conversion of cellulose into TRS. RESULTS Given the superior properties of MCMB, a novel magnetic MCMB-based solid acid with cellulose-binding domain (-Cl group) and catalytic domain (-SO3H group) was successfully prepared. Results indicated that this catalyst exhibited superior catalytic activity, recyclability and regenerability, and easy separation from the reactant. The acidic densities of -SO3H and -Cl in Fe3O4/Cl-MCMB-SO3H reached 1.77 and 1.32 mmol/g, respectively. The 68.6% TRS yield can be obtained from cellulose at 140 degrees C for 3 h in distilled water by using Fe3O4/Cl-MCMB-SO3H as the catalyst. The TRS yield still reached 61.1% after the catalyst was used six times. Importantly, through catalyst regeneration, the -SO3H density and TRS yield still reached 1.69 mmol/g and 67.3%, indicating that the catalyst exhibited excellent regenerability. CONCLUSION Such multifunctional magnetic catalyst would be a promising catalyst in the conversion of cellulose into biofuels, which was attributed to the efficient catalytic performance, magnetism, and excellent recyclability and regenerability. (c) 2019 Society of Chemical Industry