Synthesis of (all-rac)-α-tocopherol in supercritical carbon dioxide:: Tuning of the product selectivity in batch and continuous-flow reactors
Synthesis of (all-rac)-α-tocopherol in supercritical carbon dioxide:: Tuning of the product selectivity in batch and continuous-flow reactors
复制标题
DOI：
10.1002/adsc.200404312
复制
发表时间：
2005-02-01
影响因子：
5.4
通讯作者：
Ikariya, T
中科院分区：
文献类型：
--
作者：
Kokubo, Y;Hasegawa, A;Ikariya, T
以2,3,6-三甲基对苯二酚和异茶酚为原料，在超临界CO2条件下采用间歇式和连续流反应器进行缩合反应，合成了a-生育酚。在具有强Bronsted酸性的氟化分子催化剂C6F5CHTf2 （Tf = SO2CF3）催化的间歇反应中，CO2压力的增加导致α -生育酚的产物选择性显著增加，但产物收率略有下降。萃取实验和超临界流体核磁共振（scNMR）的溶解度测定表明，scCO(2)中的均相和非极性反应相是获得高选择性α -生育酚的关键。用强酸树脂Amberlyst 15作为固体酸催化剂，连续流动scCO(2)工艺进行缩合反应，得到高选择性的所需产物。
a-Tocopherol was synthesized using a condensation reaction of 2,3,6-trimethylhydroquinone with isophytol in supercritical CO2 using batch and continuous-flow reactors. In the batch reaction catalyzed by a fluorinated molecular catalyst bearing strong Bronsted acidity, C6F5CHTf2 (Tf = SO2CF3) an increase in the CO2 pressure causes a marked increase in the product selectivity for alpha-tocopberol, albeit with a slight decrease in the product yield. The solubility measurements by extraction experiments and the supercritical fluid NMR (scNMR) indicate that the homogeneous and non-polar reaction phase in scCO(2) is crucial to obtain alpha-tocopherol with high selectivity. A continuous flow scCO(2) process for the condensation reaction can be performed with a strong acid resin, Amberlyst 15, as a solid acid catalyst to give the desired product with high selectivity.