Deep eutectic solvents based in situ isolation technique for extractive deterpenation of essential oils

Essential oils, intricate blends of volatile compounds obtained from a variety of sources, play a crucial role in numerous industries. To elevate product quality, deterpenation becomes an indispensable step. This study proposes an in situ isolation technique based on deep eutectic solvents (DESs) for the deterpenation of essential oil. Salient features of relevant compounds were obtained using conductor-like screening model for real solvents (COSMO-RS) and density functional theory (DFT) methods to predict deterpenation performance. Tetrabutylammonium chloride (TBAC) was chosen based on the results of theoretical analysis and experiment to extract hydroxy-terpenoids. COSMO-RS was employed to evaluate the extraction performance at different molar ratios, and then combined with experimental analysis to determine the optimal conditions. The σ-profiles of organic solvents and their interactions with terpene revealed n-hexane to be the best solvent for purifying DES. TBAC and terpenoids were obtained through the re-extraction procedure, with a recovery of 81.8-84.4%.