Facile preparation of monolithic magnetic porous carbon acid catalysts via surface self-assembly method and their applications in conversion of xylose into furfural

Abstract

Furfural is a versatile chemical derived from pentosane-rich agricultural and forestry residues. Considered as an important platform chemical, furfural can be converted into valuable chemicals and biofuels. The furfural production from xylose was produced through the hydrolysis and subsequent cyclodehydration reaction of xylose sugar catalyzed generally by various catalysts containing SO3H. Nevertheless, their tedious multi-step preparation and the final catalysts usually in the form of fine powder make them difficult to be separated from the liquid systems after use, leading to time consumption for the industrial scale production. In the this work, novel magnetic porous carbonaceous acid catalyst (SO3H-MPBG) in the form of monoliths have successfully been prepared using sugarcane bagasse as scaffold via a self-assembly surface coating method from phloroglucinol/glyoxylic acid precursors with soft-template F127 and Fe3+ as a source for magnetic iron particles. Then facile subsequent hydrothermal sulfonation with concentrated H2SO4 at 180°C resulted in magnetic mesoporous carbon bearing SO3H group (SO3H-MPBG). The SO3H-MPBG was characterized by various techniques including XRD, FT-IR, N2 sorption analysis, elemental analysis, and VSM. A SO3HMPBG showed strong magnetism due to the presence of iron magnetic particles and possessed a BET specific surface area of 252.96 m2/g. The sample showed acceptable xylose conversion (86.13%) and furfural selectivity (55.70%) when performed at 170°C for 3 h using γ-valerolactone (GVL) as a solvent. Besides, the catalyst was easily separated after the catalytic tests using a magnet, confirming its magnetic stability.