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超临界抗溶剂过程的相平衡及应用研究

The Phase Equilibrium and Application Involved in SAS

【作者】 宋丽萍

【导师】 袁其朋; 韩布兴;

【作者基本信息】 北京化工大学 , 生物化工, 2001, 硕士

【摘要】 许多物质可溶于有机溶剂中,但不溶于超临界流体,同时,超临界流体在有机溶剂中有较大的溶解度,能引起溶剂体积膨胀,降低其溶剂化能力。因此,在适当条件下通入超临界流体可以使溶剂中溶解的溶质析出,这一过程称为超临界流体抗溶剂过程(SAS)。目前,这一新兴技术在物质重结晶、混合物或天然产物的分离、微粒制备等方面得到广泛的应用,并且具有十分广阔的前景。但对于超临界流体抗溶剂过程而言,相平衡性质随不同因素的变化规律是该技术发展和应用的关键,而目前相关的相平衡数据十分缺乏。为此本实验建立了三套不同的装置,测定了几种化合物的溶解度,并结合理论数据进行了一系列应用方面的尝试。 在第二章中,设计组装了一套测定超临界流体抗溶剂过程相平衡的装置。此装置具有平衡速度快、精度高、操作方便、可随时观察体系中相态变化等优点。利用该装置,分别研究了α-萘酚、β-萘酚在乙醇溶剂中和胆固醇在乙醇、丙酮溶剂中的溶解度。对这些体系的相平衡研究文献中尚未见报道。实验结果表明,CO2在液相中的摩尔分数随压力的升高而增大,随温度的升高而降低,溶质在溶剂中的溶解度差异对CO2的液相摩尔分数梢有影响。溶质在液相中的溶解度随压力升高而降低,随温度升高而增大。对于α-萘酚和β-萘酚来讲两者结构上的差异造成了它们在同一溶剂中溶解度的不同,从而为应用抗溶剂法分离这两种物质提供了理论依据。而对于胆固醇-乙醇和胆固醇-丙酮体系,同一物质在不同溶剂中有极大的溶解度差异,这是抗溶剂法进行重结晶的基础。 在第三章中,我们将抗溶剂过程中相平衡的理论研究与实际应用相结合,在对染料木素和大豆素的溶解度进行研究的基础上,建立了抗溶剂法分离纯化复刹昆合物的实验装置,从大豆粗提物中分离纯化了大豆异黄酮,得到的产品中染料木素含量高于卯%。这为我国大豆资源的深加工提供了一条新途径。 在第二章相平衡研究的理卯土上,第四章建立了抗溶剂重结晶装置,初步研究了超临界流体琉溶齐蛤剖旦固醇在丙酮和乙醇两种不同溶剂中重结晶中的应用,分别选择了不同的压力、温度、静置时间和初女甜渡等操作参数,比较了不同操作参参吓口不同溶剂对结晶形态的影响。实验结果表明,胆固醇在不同溶剂中结晶形态有极大的差异,在乙醇中的结晶晶粒大小远远小于在丙酮中的,并且多呈薄片状不同于在丙酮中的长棒状或块状。关键词:超临界流体抗溶剂,相平衡,溶解度,重结晶

【Abstract】 Many solutes can dissolve in some organic solvents, but do not dissolve in supercritical fluid. At the same time, supercritical fluid can largely dissolve in many organic solvents, which results in a reduction of the solvency of the organic solvents and a precipitation of the dissolved solute. This process is termed as supercritical antisolvent process (SAS) based on the state of the antisolvent So far, this rising technique has been successfully applied in recrystallizing organic compounds, separating mixtures, and producing finely comminuted particles, and its applied foreground is rather widest Whereas, phase equilibrium rule changed with different factors that involved in SAS is rather lack, which is the basis of development and application of this technology. So this report investigated the phase equilibrium involved in SAS and their applications.In Chapter II, an apparatus for investigating phase equilibrium involved in SAS was designed and constructed, which has lots of characteristics such as fast equilibrium, exact precision, facile operation and easing to observe the change of phase state momentarily. In this chapter, the solubility of a-naphthol and P-naphthol in ethanol + carbon dioxide mixtures, of cholesterol in ethanol + carbon dioxide mixtures and in acetone + carbon dioxide mixtures was studied. Solubility data of these pharmaceutical compounds in organic solvents + CO2 have not been found in literature survey. As was shown, the CO2mole fraction in the liquid phase increases with pressure and decreases with temperature. The difference between the solubility of the solutes in the liquid phases influences the CO2 mole fraction in the liquid phase. The solubility of the solutes decreases with pressure and increases withtemperature. For the system of naphthols +ethanol+CO2, there were the differences in their structure that make them behave differently. It was the differences in their solubilities that should enable them to be separated and purified from a mixture by a CO2 antisolvent process. In so far as cholesterol-ethanol/acetone-CO2 system, the solubilities of cholesterol differed in diverse solvents was the basis of recrystallizing organic compounds by supercritical antisolvent process.In Chapter III, on the basis of the phase equilibrium of genistein and daidizein, we combined SC-CO2 antisolvent process with abstraction by organic solvent, which was successfully utilized to abstract soybean isoflavone. The concentrations of Genistein in the products are higher than 90%, respectively, which implies that SAS is an effective technique for using the resource of isofavone.In Chapter IV, On the basis of phase behavior, cholesterol was recrystallizated in ethanol and acetone with CO2, respectively. The morphology of particles generated in different solvent was detected by SEM. The crystallization of cholesterol was performed by changing various operating conditions: injection rate of CO2 into the crystallizing chamber, initial concentration in ethanol or acetone, and temperature and the end pressure. The result indicated that the effect of operating parameters on the size distribution and morphology was rather evident

【关键词】 超临界流体抗溶剂相平衡溶解度重结晶
【Key words】 SCFSASphase equilibriumsolubilityrecrystallizing
  • 【分类号】O642
  • 【被引频次】1
  • 【下载频次】317
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