Patent ID: 6867296

Claim:
A process for the recovery and purification of dianhydro sugar alcohol from a vapor stream comprising the dianhydro sugar alcohol and water, comprising: a) introducing a vapor stream comprising dianhydro sugar alcohol and water into a condensation-crystallization vessel maintained at a pressure of 5-30 mm Hg and at a temperature below the melting point of the dianhydro sugar alcohol; b) partially condensing the vapor stream to precipitate the dianhydro sugar alcohol as a slurry of high purity dianhydro sugar alcohol crystals in a supersaturated mother liquor; c) removing uncondensed vapors from the condensation-crystallization vessel; d) withdrawing the slurry of high purity dianhydrosugar alcohol crystals from the condensation-crystallization vessel; and e) separating the dianhydro sugar alcohol crystals from the mother liquor.