IMPROVED METHOD FOR RECOVERING DIACETATE ESTERS OF POLYTETRAMETHYLENE ETHERS

摘要

An improved method for recovering purified diesters of polytetramethylene ethers involving the polymerization of tetrahydrofuran (THF) optionally with one or more comonomers (e.g., 3-methyl THF, ethylene oxide, propylene oxide, or the like) utilizing a solid acid catalyst (e.g., Nafion®) and a carboxylic acid with carboxylic acid anhydride (e.g., acetic acid with acetic anhydride) as molecular weight control agents wherein after polymerization product recovery involves bulk flashing of unreacted THF and stripping of remaining THF, carboxylic acid and carboxylic acid anhydride (e.g., acetic acid and acetic anhydride) by use of superheated THF. Such a process is useful in producing high purity commercial grade PTMEA that advantageously avoids problems associated with the presence of high boilers when converting to PTMEG.