【作者】 张之达；

【导师】 王安杰； Urs Welz-Biermann；

【作者基本信息】 大连理工大学 ， 工业催化， 2010， 硕士

【摘要】 中药是我国几千年来治病救人的物质基础。当前,工业上主要采用有机溶剂萃取的方法对中药中的有效成分进行提取分离。针对传统方法所面临的萃取效率低、耗时长、溶剂消耗大、环境污染严重等问题。本研究采用微波辅助萃取技术(MAE),以1-丁基-3-甲基咪唑双三氟甲基磺酰亚胺N,N-二甲基-N-(2-(2-羟基乙氧基))丙酸铵(DMHEEAP)和N,N-二甲基(腈乙基)丙酸铵(DMCEAP)3种离子液体为萃取剂,对川芎中洋川芎内酯Ⅰ、洋川芎内酯H和藁本内酯的提取工艺进行了研究。本研究系统考察了系统温度、萃取时间、固液比和原药粒度等主要因素对萃取效果的影响；利用反相高效液相色谱分析手段对目标化合物进行定量分析。以[Bmim][NTf2]为例比较了MAE和传统溶剂回流萃取法(SRE)的萃取率,并通过电子扫描显微镜(SEM)对川芎样品的母体形貌进行了研究；对3种离子液体的循环利用以及反萃回收进行了初步探索。实验结果表明,系统温度是影响萃取效率的最主要因素,随着系统温度的升高,萃取效率也随之提高,其中对[Bmim][NTf2]的影响尤为显著,而DMHEEAP和DMCEAP的萃取效率随系统温度的变化相对平稳；[Bmim][NTf2]、DMHEEAP和DMCEAP的萃取反应均能在较短的时间内完成,分别在1 min、1 min、5 min内达到平衡,值得注意的是,采用DMHEEAP和DMCEAP为溶剂时,萃取时间的延长不利藁本内酯的萃取；在所选的固液比和粒度范围内,改变萃取的固液比和样品粒度对萃取效率没有显著影响；[Bmim][NTf2]在3次循环利用中萃取效率几乎没有改变,DMCEAP经过3次循环利用萃取效率有所下降,而DMHEEAP的萃取效率下降幅度较大,以上结果是由川芎中的物质在离子液体中溶解,使离子液体粘度等性质改变,而导致萃取效率下降；经过水和正己烷的反萃,[Bmim][NTf2]中洋川芎内酯Ⅰ、洋川芎内酯H和藁本内酯的含量分别下降到反萃前的15.8%、21.3%和23.4%；而经过正己烷反萃的DMHEEAP和DMCEAP中洋川芎内酯Ⅰ、洋川芎内酯H的含量几乎没有下降,藁本内酯的含量分别下降为反萃前的39.7%和54.7%。水和正己烷分别反萃出离子液体中的极性较强和极性较弱的物质,说明通过反萃溶剂的选择,可以达到特定极性物质在离子液体中富集的目的；与SRE相比,MAE对藁本内酯萃取效率明显提高,可达46%,通过上述研究不难发现,MAE具有耗时短、效率高、溶剂用量小、离子液体可回收再用等优点,是一种高效、安全、绿色的萃取方法。该方法有望应用于天然中有效成分的提取。更多还原

【Abstract】 For the past thousands years, traditional Chinese medicine is the main source for medical treatment in China. As an important approach, extraction method is usually adopted in separating bioactive ingredients from Chinese medicine. However, volatile traditional organic solvents are commonly used in the extraction process, which would lead to environment pollution and solvents loss. At the same time, it is very time consuming and the extraction efficiency is low. In this work, in order to improve the extraction process and develop a greener process, a microwave-assisted extraction (MAE) method was investigated to extract Senkyunolide I, Senkyunolide H and Z-ligustilide from Ligusticum Chuanxiong Hort.. Three ionic liquids, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([Bmim][NTf2]), N,N-Dimethyl-N-(2-hydroxyethoxyethyl) ammonium propionate (DMHEEAP) and N,N-Dimethyl(cyanoethyl) ammonium propionate (DMCEAP), were employed as extractants in the extraction process.Four important factors such as system temperature, extraction time, solid-to-solvent ratio and particle size were studied for the three ionic liquids. Reverse HPLC method was employed for quantitative analysis. The yield of the three target ingredients was compared between [Bmim][NTf2] MAE and solvent reflux extraction (SRE), and matrix surface structure was studied by scanning electron microscope (SEM). Reuse and back-extraction of used ionic liquids were also studied.The results show that system temperature is the key factor of extraction process. And extraction efficiency increases as system temperature raise, sharp increasing for [Bmim][NTf2] and smooth increasing for DMHEEAP and DMCEAP. Extraction equilibrium can be achieved in a very short time, one minute for [Bmim][NTf2] and DMHEEAP, five minutes for DMCEAP. Extraction efficiency is not improved by increasing time, while longer extraction time leads to the decrease of extraction efficiency for Z-ligustilide in DMHEEAP and DMCEAP. For the limited solid-to-solvent ratio and particle size range experiments, solid-to-solvent ratio and particle size do not influence the extraction efficiency. Compared to SRE, [Bmim][NTf2]-MAE requires less time and gives higher extraction efficiency, an increase of 46% is reached for Z-ligustilide with [Bmim][NTf2]-MAE. Surface structure damage is noticed in MAE treated matrix through SEM study, which will be beneficial to the improvement of the extraction efficiency. No efficiency drop is noticed after the reuse of [Bmim][NTf2] for three times. But efficiency drop is noticed for DMCEAP and DMHEEAP in the reuse study, especially for DMHEEAP. This result can be attributed to property change, such as viscosity, in ionic liquids after several times of extraction, some ingredients from Ligusicum Chuanxiong Hort. are accumulated in ionic liquids. After back-extraction with water and n-hexane, concentration of Senkyunolide I, Senkyunolide H and Z-ligustilide in [Bmim][NTf2] are dropped to 15.8%,21.3% and 23.4% compared to the mount before back-extraction, respectively. Additionally, after back-extraction with n-hexane, concentration of Senkyunolide I, Senkyunolide H does not change in DMCEAP and DMHEEAP. For Z-ligustilide, the concentration drops to 39.7% and 54.7% for DMCEAP and DMHEEAP, respectively. The result shows that ingredients of different polarity can be enriched in ionic liquids by choosing different back-extraction solvents.From the above results, ionic liquid MAE method takes short time, gives high extraction efficiency and less solvent and energy consumption. It is a high-efficiency, safe and green method, which will be potentially applied in natural product extraction with large scale in the future.更多还原