Entrainer effect of water on supercritical fluid extraction of natural puroducts

在313.2K和15.0MPa下，采用静态再循环法结合在线FTIR光谱法测定了棕榈酸在超临界CO2和超临界CO2+水中的溶解度。棕榈酸在超临界二氧化碳中的溶解度随水的摩尔浓度的增加而增加，特别是在水的饱和点附近溶解度急剧增加。棕榈酸在饱和水的超临界二氧化碳中的溶解度比在超临界二氧化碳中的溶解度大160%。研究了棕榈酸的C=O伸缩谱带。棕榈酸单体和二聚体的摩尔浓度与水的浓度无关。棕榈酸单体与水相互作用的摩尔浓度随水摩尔浓度的增加而增加。在313.2K和15.0MPa下，用同样的方法测定了咖啡因在超临界CO2和超临界CO2+水中的溶解度。咖啡因在水饱和的超临界CO2中的溶解度比在超临界CO2中的溶解度大18%。用FTIR光谱法测量的咖啡因的峰的形状没有通过添加水而改变。可以认为，咖啡因和水不产生特殊的相互作用物种。

The solubilities of palmitic acid in supercritical carbon dioxide and supercritical carbon dioxide + water were measured by using the static recirculation method combined with on-line FTIR spectroscopy at 313.2 K and 15.0 MPa. The solubilities of palmitic acid in supercritical carbon dioxide increased with increasing molarity of water, and especially, the solubilities sharply increased near the saturated point of water. The solubility of palmitic acid in supercritical carbon dioxide saturated with water was found to be 160% larger than that in supercritical carbon dioxide. The C=O stretching bands of palmitic acid were investigated. The molarities of palmitic acid monomer and dimer were independent of the concentration of water. The molarities of palmitic acid monomer interacting with water increased with increasing molarity of water. On the average, one palmitic acid molecule probably interacts about six associated molecules of water in supercritical carbon dioxideThe solubilities of caffeine in supercritical carbon dioxide and supercritical carbon dioxide + water were measured by the same method at 313.2 K and 15.0 MPa. The solubility caffeine of in supercritical carbon dioxide saturated with water was found to be 18% larger than that in supercritical carbon dioxide. The shapes of the peaks for caffeine measured with FTIR spectroscopy did not change by addition of water. It can be considered that caffeine and water do not make special interaction species.