The Research Of Supercritical CO₂ Extraction Technology Of Volatile Oil From Chinese Medicine

As an environment-friendly and efficiently clean chemical separation technology, Supercritical Fluid Extraction (SFE for short) is very important in the field of extraction for Chinese medicine and other natural products. It is one of key technologies for the modernization of Chinese Medicine. Based on practical experience, the supercritical fluid extraction technique for volatile oil from Chinese medicine including schisandra, clematis chinensis, acorus gramineus and rhizoma atractylodis is studied. And the optimum technological parameter of supercritical CO₂ extraction is examined through single factor experiment and orthogonal test.Three parts of work are mainly described in the paper. The SFE is introduced in the first part including the principle, feature, application status and future prospect. The extractive technique and separation method of volatile oil from Chinese Medicine and the application of SFE on extracting effective ingredients from traditional Chinese medicinal materials are described.The technology of green supercritical extraction for volatile oil from Chinese medicine is designed in the second part. The experimental method of extracting volatile oil from Chinese medicine using supercritical CO₂ is established and the infrared spectra research technology for volatile oil from Chinese medicine is introduced.The exploring technological conditions of supercritical CO₂ extracting volatile oil from schisandra, clematis chinensis, acorus gramineus and rhizoma atractylodi are emphasized in the third part. Based on the extraction rate of volatile oil, the extraction pressure, extraction temperature, CO₂ flow rate and extraction time affecting the extract rate of volatile oil are explored, and the experimental data is analyzed by using range analysis. The optimal extraction process is determined. The results are as follows.1. The sequence of SPE factors affecting extraction rate of schisandra volatile oil is: extraction pressure > CO₂ flow rate > extraction time > extraction temperature. The optimum technological condition of supercritical CO₂ extracting schisandra volatile oil is: grinding particle size of schisandra is 60 mesh, extraction pressure 30MPa, extraction temperature 50℃, CO₂ flow rate 50～55 kg/h, extraction time 3h. Under these conditions, extraction rate of schisandra volatile oil is 16.1%. FTIR of schisandra volatile oil shows that alcohols, alkenes, esters, aldehydes and organic acids compounds are contained. 2. The sequence of SPE factors affecting extraction rate of clematis chinensis volatile oil is: extraction time> extraction temperature >extraction pressure > CO₂ flow rate. The optimum technological condition of supercritical CO₂ extracting clematis chinensis volatile oil is: grinding particle size 40 mesh, extraction pressure 30MPa, extraction temperature 55℃, CO₂ flow rate 50～55 kg/h, extraction time 3h. Under these conditions, extraction rate of volatile oil is 4.1%.3. The sequence of SPE factors affecting extraction rate of acorus gramineus volatile oil is: CO₂ flow rate > extraction pressure> extraction temperature > extraction time. The technological condition of supercritical CO₂ extracting acorus gramineus volatile oil is: extraction pressure 20MPa, extraction temperature 55℃, CO₂ flow rate 50～55 kg/h, extraction time 2.5h. Under these conditions, extraction rate of acorus gramineus volatile oil is 4.8%.4. The sequence of SPE factors affecting extraction rate of rhizoma atractylodis volatile oil is: extraction pressure > extraction time> extraction temperature> CO₂ flow rate. The optimum technological condition of supercritical CO₂ extracting rhizoma atractylodis volatile oil is: extraction pressure 30MPa, extraction temperature 45℃, CO₂ flow rate 50～55 kg/h, extraction time 3.5h. Under these conditions, extraction rate of rhizoma atractylodis volatile oil is 15.2%. FTIR shows that sesquiterpines, terpene alcohol, lesser amounts of aldehydes, ketones, phenols and organic acids compounds as well as aromatic compounds and its oxy-derivatives are contained in rhizoma atractylodis volatile oil by using SFE...