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Anionic polymerization of propylene oxide was carried out in the presence of two groups of potassium salts activated 18-crown-6 (18C6), e.g. alkoxide salts (CHOK, -PrOK, -BuOK, CHOCHCH(CH)OK, KCHO) and other salts (CbK, PhCK, PhPK, PhHBK, KK, KH, and [(CH)Si]NK) in THF at room temperature. Application of various initiating systems results in polyethers which are different in level and kind of unsaturation represented by allyloxy, - and -propenyloxy, as well as vinyloxy starting groups. In the presence of selected initiator, i.e. -BuOK unsaturation increases markedly by addition of 18C6 or C222. During the initiation step oxirane ring-opening and direct deprotonation of the monomer occur simultaneously involving in some cases also the ligand. All initiators opens oxirane ring in the β-position except -PrOK, which opens it in the β- and α-position. The mechanisms of the reactions were discussed.

The influence of initiator and macrocyclic ligand on unsaturation and molar mass of poly(propylene oxide)s prepared with various anionic system