Observations on the anionic polymerization of ethylene oxide by alkali metal naphthalene and anthracene complexes

The anionic polymerization of ethylene oxide by alkali metal naphthalenes and anthracenes was studied in DMSO and THF to determine the effects of solvent and of polycyclic hydrocarbon, and to obtain information on the mode of initiation. No propagation occurred with lithium naphthalene, and this made it possible to isolate mono- and dihydroxyethyl naphthalene, the species formed on initiation. The molecular weights obtained in the presence of DMSO were about half those obtained in THF, and were proportional to [monomer]/[initiator]. This was explained as being due to differences in initiation; i.e., formation of dimsyl anion as the true initiator in DMSO. The rate of polymerization was first order to monomer, and the molecular weights were found to increase linearly with percent inversion.