Abstract: In order to investigate their effects on the polymerization of butadiene and the microstructure of polymers, three series of nitrogen-containing compounds were added into the catalyst system of FeCl₃-(i-C₄H₉)₃Al i.e.1), pyridine, quinoline, 2,2'-bipyridine, 2,2',2"-terpyri-dine, 2,2',2",2'"-tetrapyridine;2), pyridine, 2-cyanopyridine, 2,6-dicyanopyridine; 3),triethylamine, N,N,N',N"-tetramethylethylenediamine, diethylenetriamine. The effects of concentration of ligands as well as alkylaluminum on both catalytic activity and the [η] of polymers were investigated. It was observed that the larger the number of nitrogen atomsin the ligand, the more the 1,2-structural content of polybutadieneo It is considered that the ligand coordinated to active center would occupy the empty orbitals, increasing the opportunity of trans-configuration of butadiene on the active center as well as the content of 1,2-units in polymer. The mechanism is also used to explain the difference in catalytic activities caused by various ligands.

Key words: Coordination polymerization, Butadiene, Nitrogen containing ligand, Ferric chloride, Mechanism