Optimization of Supercritical CO₂ Extraction of Essential Oil from Hemp Leaves by Response Surface Methodology

Extracted essential oil from hemp leaves was extracted by supercritical CO₂. Single factor experiments and response surface analysis were applied in the optimization of the extraction process of essential oil from hemp leaves. The influencing factors were extraction pressure (X₁), extraction temperature (X₂), extraction time (X₃) and CO₂ flow rate (X₄), and the extraction rate of essential oil from hemp leaves was used as the evaluation index for response surface analysis. Results showed that, combined with the practical operability and convenience of the extraction process, which extraction pressure 29 MPa, extraction temperature 49 ℃, extraction time 3.4 h, CO₂ flow rate 13 mL/min were determined the optimal extraction process. The actual extraction rate was 0.283%, which was close to the theoretical value of 0.281% and the actual deviation between the predicted value and the real value was −0.71%. It was suggested that supercritical CO₂ extraction had practical and development value in the extraction of essential oil from hemp leaves, which could provide a theoretical reference essential oil from hemp leaves in the future.