Preparation of polyethers via proton acid catalyzed transetherification reactions

An approach for the preparation of polyethers by a transetherification route has been developed. This approach involves the melt condensation of a diol with a specifically designed diether in the presence of a catalyst to yield polyethers with the exclusion of two moles of a low boiling alcohol, in this case methanol. The diether monomers are designed so as to contain two labile benzyl methyl ether linkages that can readily undergo a transetherification process. These diether monomers (5 a and 5 b) readily undergo transetherification polycondensation with di-, tri- and tetraethylene glycols as well as with a variety of aliphatic diols to yield polymers of moderately high molecular weights. The glass transition temperatures (Tg) of the polymers decrease with increasing length of the diol. Melting transitions (Tm) are observed only in some polymers containing aliphatic units but those with the oligo(ethylene oxide) units are completely amorphous. Preliminary ionic conductivity studies indicate that the polyethers with oligo(ethylene oxide) units could serve as excellent candidates in solid polymer electrolyte applications.