ИСТИНА

Neodymium-​based catalysts are broadly used in industry for prodn. of cis-​1,​3-​polybutadiene. However, certain details of polymn. mechanism remain unclear. Only scarce data exist on the degree of activation of Nd-​precatalyst and nature of inactive Nd-​contg. species. In this work, we studied influence of structure of neodymium carboxylates on the activity of the resp. ternary catalytic systems Nd(RCOO)​3-​AlR3-​R2AlCl in 1,​3-​butadiene polymn. Having found a correlation between substitution in the carboxylate moieties and activity of the Nd-​catalyst, we then developed a method for detn. of the no. of active sites by titrn. with a poisoning agent. This technique made it possible to study effects of various conditions of prepn. of the catalytic system on the polymn. activity and mol. wt. distribution of the 1,​3-​polybutadiene obtained.