| 摘要 |
<p>Starting from a mixture containing tocopherol, fats and/or fat derivatives, more particularly fatty acids, and optionally sterol and/or sterol derivatives, the free fatty acids present in the mixture are esterified with an alcohol and fatty glycerides are transesterified with an alcohol in the presence of a zinc oxide and/or zinc hydroxide catalyst. After the esterifications, the excess lower alcohol is distilled off from the reaction mixture. The transesterification catalyst and the glycerol present, if any, are removed and the fatty acid alkyl ester is distilled off from the mixture. Distillation of fatty acid alkyl esters can be accomplished with a packed column in sequence with a wiped film evaporator. The simultaneous recovery of tocopherol and sterol is possible. Tocopherols and sterols can be separated by the crystallization of sterols from a blend of organic solvents.</p> |
