Study On Supercritical CO₂ Fluid Extraction Of Essential Oil From Citronella

In this study,lemon citronella oil was used as the raw material to optimize the extraction process of lemon citronella oil by supercritical CO₂ fluid,and the optimum extraction process of lemon citronella oil was obtained.（1）The optimum extraction conditions of lemon citronella oil by supercritical CO₂ are as follows:the extraction temperature is 65℃,the extraction pressure is25MPa,the CO₂ flow is 25g/min,the grain size is 70 mesh,the extraction time is 90min,and the oil yield is 3.21%.The method is stable and reliable.The gas chromatography-mass spectrometry（GC-MS）was used for the analysis of volatile oil by GC-MS.32 kinds of known substances are contained in the product,The total amount is 99.03%,of which the main components are The results showed that aromatic aldehydes（32.2%）,citric acid（15.6%）,3-two methyl-3 heptanol（10.23%）,anti acacia（8.9%）,ethyl methoxide（7.75%）,and citral two ethanol acetal（6.44%）.（2）The extraction rate of fresh lemongrass and dry lemon grass was compared under the same extraction conditions.The extraction rate of fresh lemon grass of the same unit mass was higher than that of dry lemon citronella.Therefore,it is more appropriate to choose fresh vanilla from the perspective of extraction rate.（3）The size of fresh citronella and dried citronella is related to the extraction rate of lemon grass.Compared with powdered raw materials,the extraction efficiency of raw materials is relatively low,but raw materials are easy to prepare.（4）The effects of different entrainer methanol,ethanol,propanol,amyl alcohol,acetone,pentyl ketone,cyclohexanone and cyclohexanone on the supercritical CO₂extraction of citronella oil were studied.The best entrainer is pentyl alcohol,the yield of oil is 5.7%,the amount of pentyl alcohol is 11%,and the extraction rate can be improved.（5）The effective components of citronella oil extracted from lemon citronella oil were analyzed by GC-MS.