Patent attributes
The invention provides a process for the separation of a first C3 to C7 diol from a first mixture of C3 to C7 diols. The first mixture is provided to a first distillation column. An extractant is fed to the first distillation column above the first mixture. A stream comprising the first diol and the extractant is removed as a bottoms stream from the first distillation column and subjected to distillation in a second distillation column. A high purity first diol stream is removed from the top section of the second distillation column, while a used extractant stream is removed from the bottom section. The extractant is a C3 to C6 sugar alcohol or mixture thereof. The first diol is a close-boiler to and/or forms an azeotrope with one or more of the other C3 to C7 diols present in the first mixture.
