Patent ID: 8148491

Claim:
A process for producing a reaction product comprising at least one polytrimethylene ether glycol or copolymer thereof, said reaction product having a number-average molecular weight of at least about 450 g/mole, comprising: (a) reacting (1) at least one alkanediol reactant selected from the group consisting of 1,3-propanediol and oligomers of 1,3-propanediol having a degree of polymerization of 2-6, (2) optionally, at least one comonomer diol selected from the group consisting of ethanediol, C 4 through C 12 straight-chain diols, and C 3 through C 12 branched diols; and (3) at least one polycondensation catalyst, whereby a reaction mixture is produced over a reaction time; and (b) controlling the temperature of the reaction mixture over said reaction time wherein said controlling is carried out at a temperature of about 120° C. to about 250° C. with the average temperature in the first half of the reaction time being about 2° C. to about 70° C. higher than the average temperature during the second half of the reaction time; whereby a reaction product is produced.