Direct Production of Alkyl Levulinates from Cellulosic Biomass by a Single-Step Acidic Solvolysis System at Ambient Atmospheric Pressure

A simple method was invented to achieve a high yield of cellulosic biomass-derived alkyl levulinates, which have the potential to be alternative fuel additives. Alkyl levulinates, such as butyl-, pentyl-, and hexyl levulinates, were produced using single-step acid-catalyzed solvolysis of cellulosic biomass without the use of elevated pressure. Reactions were performed by refluxing alcohols such as 1-butanol, 1pentanol, and 1-hexanol at their boiling points of 117, 138, and 157 °C, respectively, with sulfuric acid at ambient pressure. After 1 hour of the reaction, the cellulosic biomass was converted into an alcohol-soluble compound, and a high yield of alkyl levulinates was achieved. Although the process involved simple treatment under atmospheric pressure, the alkyl levulinate yield was quite high: 60 to 80% based on the hexose content of the cellulosic biomass. The factors influencing the reaction, such as the accessibility to cellulose and acidity of the reaction media, could be controlled appropriately in this solvolysis system.