Preliminary Study of Alkyl Levulinate Synthesis using Aliphatic Primary Alcohols Catalyzed by Zinc Oxide

The utilization of lignocellulosic biomass for the production of energy, biofuels, and chemical products has become increasingly viable from technical, economic, and environmental perspectives, particularly when the biomass is sourced from agricultural waste. The conversion of biomass-derived levulinic acid (LA) into biofuel alkyl levulinate (AL) using alcohols as the alkoxy group (R–O) donor and reaction medium represents a promising synthesis route for AL, which is regarded as an environmentally friendly chemical product. In this study, we investigated the synthesis of alkyl levulinate from linear-chain alcohols (R–OH: 1-butanol, 1-octanol, 1-decanol, 1-dodecanol, and 1-tetradecanol) catalyzed by zinc oxide (ZnO) under the following conditions: LA : ROH molar ratio of 1 : 1, 1 wt % ZnO, temperature of 125°C, and reaction duration of 3 h. Our findings indicate that under the studied reaction conditions, the conversion of LA gradually decreases as the alcohol chain lengthens. The ester yields (%) were as follows: butyl levulinate—100, octyl levulinate—80, decyl levulinate—72, dodecyl levulinate—69 and tetradecyl levulinate—64. This trend is directly related to the physicochemical properties of the synthesized levulinates, including boiling point, polarity, and miscibility.