Patent ID: 9630938
Date: 2017-04-25
CPC Classifications: C07C,C07D

Claim:
1. A process for synthesizing and recrystallizing a dianhydrohexitol comprising the steps of: (a) converting dulcitol to dibromodulcitol by reaction of dulcitol with hydrobromic acid for from about 12 hours to about 36 hours at an elevated temperature, wherein the hydrobromic acid is at a concentration of from about 30% to about 35%, and wherein the elevated temperature is from about 35° C. to about 45° C.; (b) precipitating the product of step (a) with water; (c) washing the precipitated product of step (b) with an aliphatic ether; (d) drying the washed product of step (c) under nitrogen and vacuum; (e) converting the dibromodulcitol from step (d) to dianhydrogalactitol by reacting with a base selected from the group consisting of potassium carbonate, N,N-diisopropylethylamine (DIPEA), triethanolamine (TEA), and 1,8-diazabicycloundec-7-ene (DBU) in a polar aprotic solvent at a temperature of from about 35° C. to 45° C. for from about 16 hours to about 20 hours; (f) washing the product of step (e) with tetrahydrofuran and then with water; and (g) recrystallizing the product of step (f) from an aliphatic ketone to produce dianhydrogalactitol, and wherein the dianhydrogalactitol resulting from step (g) of the process is at a purity of at least 99.80%.