HYDROGENATION OF ISOHEXIDE PRODUCTS FOR IMPROVED COLOR

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.

主权项

1. A process for making one or more isohexides, comprising:
dehydrating one or more hexitols in the presence of an acid catalyst to form a crude dehydration product mixture including one or more isohexides; further processing the crude dehydration product mixture to separate out one or more fractions of a greater purity or higher concentration of at least one of the isohexides in the crude dehydration product mixture and one or more fractions of a lesser purity or concentration; and hydrogenating at least one of:
a) the crude dehydration product mixture;b) a neutralized crude dehydration product mixture, following a neutralization step performed on the crude dehydration product mixture;c) the product mixture following a neutralization step performed on the crude dehydration product mixture and further following a step conducted on the neutralized crude dehydration product mixture to remove ionic species therefrom;d) a greater purity or higher concentration fraction; ande) a lesser purity or concentration fraction,by reaction with a hydrogen source in the presence of a hydrogenation catalyst, under conditions effective to carry out the hydrogenation.