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This study aimed to develop a systematic method for selecting sustainable solvents for extracting terpenes from hemp. Initially, solvents were ranked using a color-coded system from the pharmaceutical industry, and renewability and affinity metrics, resulting in 16 pre-selected candidates. A multicriteria screening followed, incorporating economic, environmental, safety, and occupational health aspects to calculate a Sustainable Cumulative Index (SCI). Based on physicochemical properties and conceptual extraction design, preliminary estimates of mass, energy, and waste intensity enabled the identification of viable green solvents. Data Envelopment Analysis (DEA) was used to define a final set for further experimental testing. Ethyl acetate, ethanol, d -limonene, and water were selected and compared under standardized Soxhlet extractions of hemp threshing residues. Extractable matter and terpene content in processed biomass were 14.4 ± 3.1 wt.%, and 0.0725 wt.%., respectively. Ethanol, had low terpene yield (20.5%) and involved high energy demands in the recovery process. Ethyl acetate showed the highest yield (100%) and a full terpene profile. d -limonene exhibited a high yield (92.2%) but it might face separation challenges due to similar volatility to target monoterpenes and high boiling point. The developed method provides a structured approach to solvent selection and can support the design of green solvents.
Santaella et al. (Sun,) studied this question.