微波辅助提取及溶剂萃取法提纯甘草酸的工艺研究
文献类型：学位论文
| 作者 | 牛国光 |
| 学位类别 | 硕士 |
| 答辩日期 | 2003 |
| 授予单位 | 中国科学院过程工程研究所 |
| 授予地点 | 中国科学院过程工程研究所 |
| 导师 | 刘会洲 |
| 关键词 | 甘草酸 微波辅助提取(MAE) 溶剂萃取 提纯工 |
| 其他题名 | Microwave-Assisted Extraction of Glycyrrhizic Acid from Liquorice Root and its Purification by Solvent Extraction |
| 学位专业 | 化学工艺 |
| 中文摘要 | 甘草是中国一项非常重要的中草药资源,在医药、食品、化妆品等方面得到广泛的应用,其中的主要成分甘草酸的提取、纯化更是得到人们的关注.该论文提出了采用微波辅助提取和溶剂萃取法相结合进行甘草酸提纯的新工艺.考察了微波辅助提取时溶剂组成、氨水浓度、微波加热时间、微波加热功率、液固比、甘草粒度等因素对甘草酸回收率的影响.采用正交试验的方法对上述因素进行了影响大小分析,发现样品粒度、微波加热时间、加热功率对甘草酸的提取影响较大,液固比和氨水浓度的影响次之,乙醇浓度的影响最小.与其它的提取方法进行了比较,结果表明,微波辅助三次提取12min,甘草酸的回收率大于80%,相当于热回流提取90min,室温浸泡10h,索氏提取5h.经微波照射后,甘草酸的回收率明显升高,这可能是微波的照射可破坏样品组织结构,从而加速了对甘草酸的提取. |
| 英文摘要 | Liquorice, as an important traditional Chinese medical herb, has been widely used in the fields of pharmacy, food, cosmetics, etc.. Glycyrrhizic acid (GA) is one of the main ingredients in liquorice. Widespread attention has been recently paid to isolation and purification of GA from liquorice roots. In the work, a novel method of microwave-assisted extraction (MAE) combining with solvent extraction was suggested for GA purification. First of all, influence factors, such as solvent compositions, ammonia concentration, microwave heating time, heating power, liquid/solid ratio and sample granularity, were optimized respectively to maximize the MAE efficiency. On the basis of above experimental results, orthogonal experiments were designed to determine the degree of these factor effects on MAE efficiency. The results showed that sample granularity, microwave heating time and power had remarkable effects on increasing the MAE efficiency, liquid/solid ratio and ammonia concentration were secondary, and ethanol concentration had the least effect within the range of experiments designed. Compared with other methods, such as heating reflux, Soxhlet extraction or marinating extraction, MAE could get higher GA recovery in relatively short time. After three time MAE, total heating time was about 12 min, the recovery of GA reached above 80% which was similar to the results obtained by reflux for 90min, by marinating extraction for 10 hr., or Soxhlet extraction for 5 hr. Further study suggested that plant cell tissues and structure were probably destroyed under direct microwave irradiation, as a result GA was easily extracted from liquorice roots and the higher recovery rate was obtained. Solvent extraction and stripping of GA were studied with 2-ethylhexanol, n-hexanol, TBP, TRPO as extractants in model system. Factors affecting the efficiency of solvent extraction and stripping of GA were investigated respectively, including pH, stirring time, organic solvent concentration, phase ratio, and temperature. It showed that GA can be easily extracted to oil phase from aqueous phase in the molecular state, and stripped back to aqueous phase again when being transformed into the ionic state by adjusting pH. Solvent extraction or stripping of GA was a quick process where the eqillibrium of GA distribution between aqueous phase and oil phase was established within 3-5 min of magnetic stirring. For above extractants, the extraction rate of GA increased at the same extractant concentration with the sequence of TRPO > TBP > n-hexanol > 2-ethylhexanol. The solvent extraction by 2-ethlyhexanol and n-hexanol was a heat absorbing process, with AH about 14.02kJ/mol and 0.18kJ/mol respectively, in this case, raising temperature resulted in the increase of GA extraction rate. Comparatively solvent extraction of GA with TBP or TRPO was a heat producing process with AH -4.35kJ/mol or -4.83kJ/mol, and the extraction rate of GA gradually decreased with the increase of temperature. The extraction mechanism was also studied by the methods of UV, TEM, viscosity and distribution ratio analysis. It was suggested that GA was extracted into organic solvent in the form of aggregation rather than single molecule. As a result, constant ratio of extractant to GA in their complexes was not obtained, and the solvation number changed with GA and extractant concentration in oil phase. Compared with the results of model system, the extraction rate of GA decreased in practical system, when using 2-ethylhexanol, n-hexanol, TBP and TRPO as extractants. Furthermore, emulsification could easily occur during the process of extraction or stripping, probably due to the existence of other components in marinating aqueous solution. HPLC chromatograms showed that solvent extraction and stripping of GA had a certain selectivity. Purification of GA was easily achieved by adjusting pH properly during the process of extraction or stripping based on the property of GA. |
| 语种 | 中文 |
| 公开日期 | 2013-09-16 |
| 页码 | 105 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1370]  |
| 专题 | 过程工程研究所_研究所（批量导入） |
| 推荐引用方式 GB/T 7714 | 牛国光. 微波辅助提取及溶剂萃取法提纯甘草酸的工艺研究[D]. 中国科学院过程工程研究所. 中国科学院过程工程研究所. 2003. |
入库方式： OAI收割
来源：过程工程研究所
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