Synthesis of functional polyethylene via copolymerization of ethylene and substituted allene using bis(β-enaminoketonato)titanium catalysts

Abstract

Novel copolymerization of ethylene with substituted allenes (CH2=C=CH-R, 1: R=n-butyl, 2: R = n-octyl) using bis(β-enaminoketonato)titanium catalysts [PhN=C(R2)CHC(R1)O]2TiCl2 (1a: R1 = CF3, R2 = CH3; 1b: R1 = Ph, R2 = CF3) has been investigated. In the presence of modified methylaluminoxane, these catalysts can copolymerize ethylene with substituted allenes, affording copolymers with unimodal molecular weight distributions and homogeneous compositions. By varying the reaction conditions, the comonomer incorporation can be tuned in the range of 0–3.6 mol%. 1H-NMR spectra reveal that the copolymerization proceeds through 1,2-insertion fashion of allene comonomer exclusively, and the regioselective nature maintains under various reaction conditions. The retained intra-chain double bond can be converted into the epoxy group under mild conditions.