羟基柠檬酸的合成研究

Study on Synthesis of Hydroxycitric Acid

该文以柠檬酸为原料 ,经过脱水制取乌头酸 ,再由乌头酸氧化制取羟基柠檬酸。分别研究了乌头酸及羟基柠檬酸的优化工艺 ,乌头酸的优化工艺条件是 1mol的羟基柠檬酸用 5 6 %硫酸 2 70mol,于 140℃反应 7h ,得到乌头酸精品熔点为186℃分解 ;废酸及未分解的柠檬酸循环使用 ,柠檬酸回收率达 2 8% ,浓硫酸回收率达 6 5 %。羟基柠檬酸的优化工艺条件是以n氧化剂 与n乌头酸 之比为 2∶1,反应时间 16h ,反应温度 5 0℃得到羟基柠檬酸 ,产品收率约 80 %。

Hydroxycitric acid is prepared by citric acid.Hydroxycitric acid is obtained by aconitic acid with oxidation,which is obtained by citric acid with dehydration.The optimum conditions of aconitic acid and hydroxycitric acid are studied separately.The optimum condition for aconitic acid is that 1 mol citric acid reacts with 56 % sulfuric 270 ml to obtain aconitic acid after 7-hour reflux,in 140 ℃.Its' m.p. is 186 ℃.Because waste acid and unreacted citric acid are used cyclically,reclaimed citric acid is 28 % and reclaimed sulfuric acid is 65 %.The optimum condition for hydroxycitric acid is that 2 mol oxidant reacts with 1 mol aconitic acid in 50 ℃,for 7-hour,and obtains hydroxycitric acid,whose yield is about 80 %.