Patent ID: 7164046

Claim:
A process of manufacture of polytrimethylene ether glycol comprising the steps of: (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 and hydrolyzing the acid esters formed during the polycondensation to form a hydrolyzed mixture containing the polytrimethylene ether glycol and the hydrolyzed acid esters; (c) adding one or more water-soluble, inorganic compounds to the hydrolyzed mixture to form an aqueous-organic mixture comprising (i) an organic phase containing polytrimethylene ether glycol and residual acid polycondensation catalyst from the polycondensing, and (ii) an aqueous phase, wherein the water-soluble, inorganic compounds are selected from the group consisting of an inorganic salt and an inorganic base; (d) separating the aqueous phase and the organic phase; (e) optionally adding base to the separated organic phase to neutralize the residual acid polycondensation catalyst by forming salts of the residual acid polycondensation catalyst; (f) removing residual water from the organic phase; (g) separating the organic phase into (i) a liquid phase comprising polytrimethylene ether glycol, and (ii) a solid phase comprising the salts of the residual acid polycondensation catalyst and the base which is unreacted.