Synthesis, characterization and ethylene polymerization activity of titanium, zirconium and hafnium compounds derivatives from symmetric oxamide

New non-metallocene polymerization catalysts derived from 1,2-bis(3,5-di-tert-butyl-2-hydroxiphenyl)oxamide (L) and transition metals (Ti, Zr, Hf) were synthesized and tested for ethylene polymerization reactions. The syntheses were carried out from various bases and solvents (triethylamine/toluene, NaH/THF and NaOH/methanol). The zirconium compound (5) showed the highest catalytic activity (the polyethylene molecular weight was 98,000 Da) and polydispersity index (1.8–2.0) when n-heptane was used as solvent. In terms of Tm and crystallinity, this catalyst produced the highest density linear polyethylene.

Graphical abstractIn this articule, we discuss synthesis, characterization and the polimerization activity of titanium, zirconium and hafnium heterocycles complexes derived from 1,2-bis(3,5-di-tert-butyl-2-hydroxyphenyl)oxamide. The catalytic activity and polymer mass were measured under several polymerization conditions. The zirconium catalyst exhibits the highest activity and produces high density linear polymers.Figure optionsDownload full-size imageDownload as PowerPoint slide