基于液气射流技术改进单宁酸氧化制备鞣花酸的工艺

Improved tannic acid oxidation process for preparing ellagic acid based on liquid-gas jet technology

摘要:

针对鞣花酸在实际生产过程中耗时长、纯度低等问题，以单宁酸为基质采用液气射流氧化法制备鞣花酸，考察了金属离子、单宁酸浓度、反应温度和反应时间对鞣花酸得率及纯度的影响。进一步探究了溶剂法、结晶法、碱溶酸沉法、反溶剂法对鞣花酸纯度的影响，并通过高效液相色谱、红外光谱、紫外可见分光光谱和热重对鞣花酸高纯度的样品进行表征。结果表明，其制备的较优工艺条件为：2.5%单宁酸溶液中引入金属离子Na （即NaOH）调节反应液pH至8.5，反应温度20℃，反应时间6 h，该条件制备的鞣花酸经碱溶酸沉后产率为46.72%、纯度84.55%；选取甲醇溶剂洗涤法在65℃条件下处理1h，鞣花酸的纯度达98.13%，回收率为75.03%，提高了鞣花酸的热稳定性。液气射流氧化法与溶剂洗涤法相结合，大幅缩短制备鞣花酸的反应时间并明显提高其纯度，有望在工业生产中提高鞣花酸的生产效率并拓宽其在医药和化妆品领域的应用。

Abstract:

In view of the problems of long time and low purity of ellagic acid in the actual production process, ellagic acid was prepared using tannic acid as the matrix by a new high-throughput interface oxidation method. The effects of metal ions, tannic acid concentration, temperature and time on the yield and purity of ellagic acid. The influence of solvent method, crystallization method, alkali-soluble acid precipitation method and on the purity of ellagic acid was further explored. The samples were characterized by high performance liquid chromatography, infrared spectroscopy, ultraviolet-visible spectroscopy and thermogravimetry Characterize. The results show that the better process conditions for its preparation are: 2.5% tannic acid solution with metal ion Na (NaOH) to adjust the pH of the reaction solution to 8.5, reaction temperature 20 ℃, reaction time 6h, ellagic acid prepared under this condition After alkali-soluble acid precipitation, the yield is 46.72% and the purity is 84.55%; the methanol solvent washing method was used for 1h at 65℃, the purity of ellagic acid reached 98.13%, and the recovery rate was 75.03%, the thermal stability of ellagic acid was improved. The combination of liquid-gas jet oxidation method and solvent washing method greatly shortens the reaction time for preparing ellagic acid and significantly improves its purity. It is expected to increase the output rate of ellagic acid in industrial production and broaden its application in the fields of medicine and cosmetics.