Formation of 4-Alkoxy-γ-valerolactones from Levulinic Acid and Alcohols during Storage at Room Temperature

Article abstract of DOI:10.1021/jf00051a041

Levulinic acid (LA) is a flavor ingredient used for many products.During the storage of LA in alcohols at room temperature, chemical changes were observed.Specifically, two groups of compound were formed, esters of LA and 4-alkoxy-γ-valerolactones.All of these compounds were identified by spectral data and synthesis.Mechanistically, it is proposed that the alcohol reacts reversibly either with the keto group of LA to form the ester.All of the data obtained from this study suggest that during the initial stages of storage the reactions are kinetically controlled toform the 4-alkoxy-γ-valerolactone more than the ester; however, as the reactions proceed toward equilibrium, they become thermodynamically controlled to form the ester more than the 4-alkoxy-γ-valerolactone.Keywords: Alkyl levulinates; benzyl levulinate; ethyl levulinate; 2-phenylethyl levulinate; cis-3-hexenyl levulinate; geranyl levulinate; 4-alkoxy-γ-valerolactone; 4-(phenylmethoxy)-γ-valerolactone; 4-ethoxy-γ-valerolactone; 4-(2-phenylethoxy)-γ-valerolactone; 4-(cis-3-hexenoxy)-γ-valerolactone; geranioxy-γ-valerolactone; levulinic acid