2442-21-9Relevant articles and documents
Ti (IV) complexes of some heterocyclic ligands synthesis, characterization and ethylene polymerization activity
Elagab, Hamdi Ali
, p. 681 - 700 (2016/05/09)
31 complexes of bis - (benzimidazole, benzothiazole and benzoxazole) compounds with Ti (IV) metal centers were synthesized, characterized, activated with methylalumoxane (MAO) and then tested for catalytic ethylene polymerization. The activities of the various catalysts were found to be functions of the hetero atoms in the ligand frameworks. The highest activity was obtained with 39/MAO (573 kg PE/mol cat. h). The produced polyethylenes showed high molecular weights (up to 1.5 × 106 g/mol) and broad molecular weight distributions (PD = 65). This could result from different interactions of the MAO counterion with the heteroatoms of the catalyst ligand generating different active sites.
Bis(benzimidazolyl, benzothiazolyl, and benzoxazolyl)benzene complexes as catalysts for ethylene polymerization
Elagab, Hamdi Ali,Alt, Helmut G.
, p. 100 - 111 (2015/03/05)
A series of 36 complexes of 1,2-bis(benzimidazolyl, benzothiazolyl and benzoxazolyl)benzene compounds with Ti(IV), Zr(IV) and V(III) were synthesized and characterized. After activation with methylaluminoxane (MAO), they showed variable activities towards ethylene polymerization. Parameters like the steric conditions and the number and nature of the hetero atoms at the precatalyst molecule, the concentration of the cocatalyst MAO, the nature of the transition metal and the reaction temperature have a strong influence on the performance of the corresponding catalysts. The polymerization activity of the catalyst system [1,2-bis(benzimidazolyl)benzene zirconium tetrachloride] 20/MAO was investigated under various polymerization conditions. Studies of structure-property relationships allowed the optimization of catalysts. Bimodal or multimodal resins indicate the existence of more than one active site in the polymerization reaction in one type of homogeneous catalyst.
