Copolymerization of Ethylene with 10-Undecen-1-ol Using Highly Active Vanadium(Ⅲ) Precatalysts Bearing Bis(imino)pyrrolyl Ligands

The copolymerizations of ethylene with 10-undecen-1-ol have been investigated using vanadium precatalysts, bis(imino)pyrrolyl vanadium(III) complexes 1-3, 2,5-C4H2N(CH=NR)2VCl2(THF)2 R = C6H5(1), 2,6-iPr2C6H3(2), C6F5(3)], and the iminopyrrolyl and β-diketiminate ones for comparison. The polar monomer was pretreated by diethylaluminium chloride(present also as the cocatalyst) before the copolymerization. The monomer reactivity ratios were evaluated using the Fineman-Ross method. The ligand structure considerably influenced the catalytic activity and tolerance towards the polar monomer, the polar monomer incorporation and the molecular weights of the resultant copolymers. The bis(imino)pyrrolyl vanadium complexes exhibited promising catalytic performance for the copolymerization, and a high catalytic activity up to 3.84 kg/mmolv·h with a high comonomer incorporation of 14.0 mol% was achieved by complex 3 under mild conditions.