Abstract: Different kinds of modifiers were chosen, which add to the process of extracting citrus essential oil in supercritical CO2 fluid, the results showed that the technological conditions of the most amount of (d)-Limonene were ethanol, the ratio of mol flow rate CO2 is 5%, extracting container temperature 40 ℃, extracting container pressure 16 MPa, with 59.03‰ essential oil in separating container I; the optimum technological parameters of de-terpene were ethyl acetate, the ratio of mol flow rate CO2 is 7%, extracting container temperature 45 ℃, extracting container pressure 16 MPa, with 8.79‰ essential oil in separating container II. According to the FIR equipment, we may prove that modifiers and essential oil may make action in unsaturated chemical bond. So it made the higher extraction ration than only use supercritical CO2 fluid.

Key words: supercritical CO2 fluid, modifiers, Jinchen essential oil, IR