Efficient deterpenation of lemon essential oil enhanced by a levulinic acid-based natural eutectic solvent

Deterpenation of lemon essential oil is essential for improving product quality and enriching bioactive compounds but challenging due to the weak selectivity caused by mildly polar compounds like citral and limonene. In this work, an efficient extractive deterpenation process was developed using a levulinic acid (LEA)-based natural eutectic solvent (NAES). Water was identified as the optimal natural hydrogen bond acceptor, with its content modulating the strength of hydrogen bonding between NAES and the target solute citral. A 2 wt% water content was employed for citral extraction, while higher water content aided citral recovery. Furthermore, hexane was selected as the anti-extractant from 2508 solvents to enhance selectivity and reduce limonene co-extraction. After sequential extraction and back-extraction with water and hexane, followed by vacuum distillation, high-purity citral (96.2 wt%) was obtained. The hydrous LEA NAES was recovered and reused effectively. This work presents an efficient and recyclable strategy for the extractive deterpenation of lemon essential oil using NAES.