| 摘要 |
A process is described for making isohexides, comprising dehydrating one or more hexitols with an acid catalyst to form a crude dehydration product mixture including one or more isohexides, further processing the mixture to separate out one or more fractions of a greater purity or higher concentration of at least one of the isohexides, and hydrogenating at least one of a) the crude dehydration product mixture, b) a neutralized crude dehydration product mixture, following a neutralization of the crude dehydration product mixture, c) the product mixture following a neutralization step and further following a step to remove ionic species therefrom, d) a greater purity or higher concentration fraction, and e) a lesser purity or concentration fraction, by reaction with a hydrogen source in the presence of a hydrogenation catalyst. Hydrogenation improves the color and/or color stability of the material, especially of a finished isohexide product. |
