A process of manufacture of polytrimethylene ether glycol comprising:
(a) polycondensing reactant comprising diol selected from the group
consisting of 1,3-propanediol, 1,3-propanediol dimer and 1,3-propanediol
trimer or mixtures thereof in the presence of acid polycondensation
catalyst to form polytrimethylene ether glycol; (b) adding water to the
polytrimethylene ether glycol to form an aqueous mixture; (c) heating the
aqueous mixture to hydrolyze acid esters formed during the acid catalyzed
polycondensation; (d) adding to the hydrolyzed aqueous mixture organic
solvent that is miscible with polytrimethylene ether glycol to form (i)
organic phase containing the polytrimethylene ether glycol and residual
acid polycondensation catalyst from the polycondensing and (ii) aqueous
phase; (e) separating the aqueous phase and the organic phase; (f) adding
base to the separated organic phase to neutralize the residual acid
polycondensation catalyst by forming salts of the residual acid
polycondensation catalyst; (g) separating the organic phase into (i)
liquid phase comprising the polytrimethylene ether glycol, the organic
solvent and any residual water, and (ii) solid phase comprising the salts
of the residual acid polycondensation catalyst and the base which is
unreacted; and (h) removing the organic solvent and the residual water
from the liquid phase to obtain polytrimethylene ether glycol.