Abstract |
Post-grafting methodologies were used to prepare aryl-organosulfonic acid functionalized silica nanoparticles (SO3H-aryl-SiO(2)NPs) as highly active heterogeneous acid catalysts for catalytic esterification of free fatty acids (FFA) and levulinic acid (LA), and aldol condensation of furfural with 3-methylfuran, well known renewable feedstocks for biodiesel and fuel additives production. The chemical and structural characterization of the SO3H-aryl-SiO(2)NPs confirmed the success of the functionalization. Complete conversion for all FFA was observed using SO3H-aryl-SiO(2)NPs after 2 h of reaction. SiO(2)NPs\_CSPTMS showed to be the most active and stable catalyst with no significant loss of activity in the first 5 cycles. In the LA esterification in the presence of an alcohol, complete conversion and selectivity and high reusability were observed (e.g., 83.2\% yield after 10 cycles in the presence of 1-propanol, SiO(2)NPs10\_CSPTMS, at 120 degrees C and 2h reaction). Finally, aldol condensation of furfural and 3-methylfuran had been performed using SiO(2)NPs\_CSPTMS catalysts with almost 100\% yield after 10 min at 65 degrees C, high stability and reusability for 7 catalytic cycles. In general, the prepared SO3H-aryl-SiO(2)NPs have demonstrated promising catalytic performance for transformation of biomass-derived feedstocks into biodiesel and fuel additives. |