Method for manufacturing diacetate esters of polytetramethylene ethers

In a process for producing diesters of polytetramethylene ethers by polymerizing THF optionally with one or more substituted THF or alkylene oxide comonomers in a polymerization reactor utilizing a solid acid catalyst and a carboxylic acid with carboxylic acid anhydride as molecular weight control agents, wherein the improvement comprises the steps of:

• (i) setting the pressure of the polymerization reactor such that the evaporation and/or condensation of THF effectively controls the reaction temperature;
• (ii) withdrawing from the polymerization reactor at reduced pressure and under vacuum sufficient evaporated THF to remove the exothermic heat of reaction associated with polymerization to effectively control reaction temperature;
• (iii) condensing the evaporated THF of step (ii);
• and (iv) returning condensate from step (iii) to the polymerization reactor thus simultaneously during polymerization achieving removal of the heat of reaction by operating under solvent/monomer evaporative reaction conditions.