Study on the initiation step of vinyloxirane and 3-butenyloxirane polymerization by alkalide K−, K+(15-crown-5)2

Transfer of one electron from potassium anion of alkalide K−, K+(15-crown-5)2 to the double bond of vinyloxirane results in the oxirane ring opening exclusively in the α-position. K0 and radical anions are formed in the process. The former transfers the second electron mainly to the next monomer molecule. The latter dimerize to potassium glycoxides, which initiate the polymerization of vinyloxirane. The introduction of two CH2 groups between the double bond and the oxirane ring changes the way of electron transfer. The oxirane ring of 3-butenyloxirane becomes the electron acceptor and its opening occurs in the β-position. In this case K0 transfers the second electron to the primarily formed radical anion giving an organopotassium intermediate. It reacts with crown ether. Potassium alkoxides are the reaction products. They become the real initiators of 3-butenyloxirane polymerization.