Highly efficient non-microwave instant heating synthesis of hexyl levulinate fuel additive enhanced by sulfated nanosilica catalyst

Highly active and recyclable sulfated silica nanocatalyst for the synthesis of hexyl levulinate (HL) is reported. The sulfated catalysts, Sn-BLA (n = 15 or 30 mu L of H2SO4 added), are prepared via sulfation upon amorphous bamboo leaf ash (BLA) under non-microwave instant heating condition (100 degrees C, 1.5 h). The spectroscopy and microscopy results reveal that silica nanoparticles (28 nm) with Bronsted (isulfate group) and Lewis (sulfate group) acid sites are produced upon sulfation treatment. The sulfur containing acid groups covalently bound on the mesosilica surface are very active in the esterification of levulinic acid and hexanol where S30-BLA presents excellent catalytic activity (95.2% conversion, 98.0% selective to HL) at 90 degrees C for 7 min, which is far more superior than the previously reported catalysts. The S30-BLA catalyst is reusable with slight decrease in catalytic activity after six consecutive runs, suggesting an economical and environment friendly route to biomass utilization.

Automated summary

Highly active and recyclable sulfated silica nanocatalyst has been developed for the synthesis of hexyl levulinate. The catalyst exhibits excellent catalytic activity and reusability, making it a promising candidate for biomass utilization.