Patent ID: 7074969

Claim:
A process of making 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 an acid polycondensation catalyst at a temperature of at least about 150Â° C. to obtain a polytrimethylene ether glycol reaction mixture; and (b) purifying the reaction mixture, without hydrolysis of the reaction mixture, to obtain polytrimethylene ether glycol by: (i) adding to the reaction mixture substantially water-insoluble base in an amount sufficient to neutralize the acid polycondensatian catalyst and obtain a neutralized polytrimethylene ether glycol reaction mixture; (ii) contacting the neutralized reaction mixture with filter aid having a permeability no greater than about 0.150 Darcy; and (iii) separating the polytrimethylene ether glycol from the filter aid.