Synthesis of eugenyl acetate by immobilized lipase in a packed bed reactor and evaluation of its larvicidal activity

Abstract Eugenol esters, including eugenyl acetate, has been intensively investigated because of its beneficial antioxidant, antimicrobial, antitumor and potential larvicidal properties. Recent studies verified that small amounts of eugenol esters are effective against the development of larvae of Aedes egytpti . Packed bed reactors (PBR) have been employed for the synthesis of a variety of esters, as it is essential to assess some process parameters such as molar ratio of substrates, operating temperature and reaction residence time. Based on these aspects, the objective of this study was to evaluate the effect of molar ratio of eugenol and acetic anhydride, reaction temperature and substrates flow rate on the synthesis of eugenyl acetate esters in a packed bed reactor, using Lipozyme TL IM lipase as catalyst, and to determine the larvicidal activity of the obtained ester against larvae of A. aegypti . The optimal condition was obtained with flow rate of 0.1 mL min −1 , 55 °C and 1:5.82 (eugenol:acetic anhydride) molar ratio, affording a conversion value of about 93%. Further, the potential toxicity of A. aegypti larvae increased under the effect of eugenyl acetate, presenting a LC 50 of 0.102 mg mL −1 , which demonstrates its usability as a natural compound that can be employed in commercial larvicidal formulations.