The influence of macrocyclic ligands and water on propylene oxide polymerization initiated with anhydrous potassium hydroxide in tetrahydrofuran

It was found that presence of macrocyclic ligands, such as coronand 18C6 and cryptand C222 influence unsaturation of polyethers obtained by the polymerization of propylene oxide (PO) initiated with highly dispersed anhydrous KOH in tetrahydrofuran at room temperature. Polymerization carried out at low initial concentration of PO and quenched with CH3I resulted in the polymers without terminal single bondOH groups. In this case unsaturation is very high and is represented mainly by cis-propenyloxy starting groups due to isomerization of double bonds of allyloxy groups. The unsaturation increases in the presence of ligands. However, polymers synthesized at higher initial concentrations of PO possess OH terminal groups and addition of ligands diminishes unsaturation which is represented mainly by allyloxy starting groups. The highest molar mass of polymers obtained is Mn = 9000. KOH⋅H2O/18C6 appeared to be also effective initiator giving the polymers which contain great amount of terminal single bondOH groups and very low unsaturation; their molar masses are rather low (Mn = 2400–2900).