Hydrogen-Transfer Alternating Copolymerization of P-Ethenyl-N-n-propylphosphonamidic Acid Ethyl Ester with Cyclic Phosphonites Involving Oxidation-Reduction Process

Abstract

ABSTRACT:The present paper describes the alternating copolymerization of P-ethenyl-Nn-propylphosphonamidic acid ethyl ester (1) with cyclic phosphonites (2). The copolymerization took place without added catalyst to produce I : 1 alternating copolymer 3. During the copolymerization the oxidation-reduction reaction of monomers occurred. Monomer 1 behaved as an oxidant monomer (M0 J whereas 2 acted as a reductant monomer (M"d). The structure and composition of copolymers were determined by 1 H and 31 P NMR spectra as well as the hydrolysis experiments. The copolymerization is reasonably explained by a mechanism of propagation via zwitterion intermediates. The apparent monomer reactivity ratios determined in benzonitrile at 130°C were r1 =0.00 and r2 c,ix-membe«dl=0.34.