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High pressure phase equilibrium of citrul essential oil and soy bean oil constituents in supercritical CO2
|關鍵字:||超臨界二氧化碳;supercritical CO2;密度;溶解度;天然物模式溶質;分配係數;density measurement;P-x-y diagram;natural materials;distribution coefficient||出版社:||化學工程學系||摘要:||
In this study a new apparatus was capable of providing P-x-y equilibrium data for five binary mixtures over a wide range of pressures and temperatures. Liquid and vapor densities for carbon dioxide + each model compound were individually measured by using the system consisting of two vibrating tube densitometers. Then P-x-y diagram of each system could be obtained by means of the present apparatus at 313 K and 333 K and pressures up to 24.2 MPa. For linalool and limonene system vapor-phase density was almost merged with liquid-phase density, when pressure increased near the critical point of the mixture. At 333 K, solubility of limonene in CO2 was greater than that of linalool in carbon dioxide. For all temperatures investigated, the solubility of linoleic acid in CO2 is the highest. CO2 solubility in liquid phase increased with applied pressure but decreased with increasing temperature, except for tocopherol in CO2. The distribution coefficients of five model compounds were increased with increasing pressure, and decreased with increasing temperature. Linoleic acid in three soy bean oil constituents have the greatest distribution coefficient. Therefore, it is predictable that supercritical CO2 extraction of these three components, linoleic acid will have the highest equilibrium concentration.
本研究以定體積靜態式循環平衡裝置，並聯震盪管密度儀量測二氧化碳與兩種橘皮油成份及其與三種黃豆油指標成分之汽、液相平衡。溫度範圍313 K至333 K，壓力高達24.2 MPa。實驗結果顯示，汽相流体之密度隨著壓力的升高呈緩慢增加，二氧化碳與沉香醇及其與檸檬烯的汽、液相混合流体密度於高壓時，有結合在一起的趨勢。定溫時檸檬烯在二氧化碳相之溶解度大於沉香醇在其中的溶解度。相同溫度時，二氧化碳與亞麻油酸、維生素E、油酸三甘酯三種混合液的臨界壓力均高於其與沉香醇、檸檬烯兩種混和液的臨界壓力。五個平衡系統數據均顯示，CO2的分配係數(KCO2)會隨著壓力的升高緩慢減少趨近於1。五個模式溶質的分配係數均隨著壓力的升高有比較明顯的增加，且低溫有較高的分配係數。亞麻油酸在三種黃豆油指標成份中的K值最大。因此可預測313 K至333 K之二氧化碳平衡式萃取時，壓力小於24.2 MPa時亞麻油酸在超臨界二氧化碳相將會有較高的平衡濃度。
|Appears in Collections:||化學工程學系所|
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