| 摘要 |
Disclosed is a method for preparing DL- alpha -tocopherol with a high yield through the condensation of isophytol or phytol derivatives with trimethylhydroquinone (TMHQ) in the presence of a Zn-Al heterogeneous catalyst system. At 80 to 120 DEG C, the condensation is carried out for 2 to 7 hours in the presence of a Zn(II) ion-coated alumina-silica catalyst in an n-heptane solvent. The synthetic Zn(II) ion-coated silica-alumina synthetic catalyst system can remarkably reduce side-reactions upon the condensation of isophytol or phytol derivatives and TMHQ, thus producing DL- alpha -tocopherol with a high purity at a high yield. In addition, the catalyst system is greatly convenient to handle and therefore apply for continuous reactions for the preparation of DL- alpha -tocopherol. With these advantages, the catalyst system can be effectively used in preparing highly pure DL- alpha -tocopherol at a high yield on a commercial scale. |
