Arylsulfonic acid functionalized hollow mesoporous carbon spheres for efficient conversion of levulinic acid or furfuryl alcohol to ethyl levulinate

A series of arylsulfonic acid functionalized hollow mesoporous carbon spheres (ArSO3H-HMCSs) with controllable ArSO3H loadings (1.8 and 3.2 wt%) and inner diameters (120-260 nm) were successfully prepared by chemical bonding ArSO3H groups to furfuryl alcohol-derived hollow mesoporous carbon spheres via diazonium coupling. The morphology, textural properties and chemical structure of as-prepared ArSO3H-HMCSs were well characterized by TEM, FESEM, nitrogen gas porosimetry measurement, XRD measurement, Raman scattering and FT-IR spectroscopy as well as XPS surface probe technique. As the novel solid acid catalysts, the catalytic activity and stability of the ArSO3H-HMCSs were evaluated by synthesis of ethyl levulinate from biomass-derived platform molecules, levulinic acid or furfuryl alcohol. The obtained excellent acid catalytic activity in comparison of other carbon-based-SO3H catalysts such as ArSO3H-functionalized ordered mesoporous carbon, sulfonated hollow mesoporous carbon spheres as well as sulfonated incompletely carbonized D-glucose and cellulose was explained in terms of their strong Bronsted acidity and perfect hollow nanospherical morphology with thin mesoporous shell. (C) 2015 Elsevier B.V. All rights reserved.