水解及酯化副反應對轉酯化外消旋Naproxen動態動力分割之影響

• Main Authors: Yu-chi,Cheng, 鄭育奇
• Other Authors: 蔡少偉
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/14773695758097552073

碩士 === 國立成功大學 === 化學工程學系 === 88 === Owing to the water molecules adsorbed on the lipase, it is imperative to give hydrolysis side reaction and hence decreases the yield for the product in the kinetic resolution of racemates by transesterification. Thus, the purpose of this research is to investigate the effects of controlling initial water activity of the organic reaction medium in lipase-catalyzed enantioselective trans-esterification of Naproxen thioester. Various saturated aqueous solutions have been employed to decrease the water content or water activity of the reaction organic medium. Change of the water activity has nearly no influence on the lipase activity for trans-esterfication. However, owing to the decraese of water content for reaction, the hydrolysis rate was largely reduced. By employing organic amine as the racemization catalyst in the lipase catalyzed kinetic resolution process and further controlling the initial water activity of organic medium, it is possible to overcome the maximum 50 % conversion and simultaneously to obtain high stereopurity for the desired enantiomer product, cmparing to conventioal kinetic resolution process. Agreements between the experimental and theoratical results were found in the dynamic kinetic resolution of Naproxen thioester when hydrolysis and esterification side reactions were considerd.