Influence of external N‐containing donors on the neodymium‐based catalytic system for 1,3‐butadiene polymerization

Abstract

AbstractEvaluation of the heteroatom tolerance capability of neodymium‐based precatalysts and its accompanied catalytic influences is of great significance for industrial production of polybutadienes because the corresponding active species is highly sensitive to heteroatom‐based impurities that are usually inevitable in the polymerization system. Based this consideration, the present research disclosed a systematical study of the influence of N‐containing donors on a ternary Nd‐based system of Nd(vers)3/DIBAH/TEA/EASC. It was found that the presence of 1% of such donors, regardless of their types that bears different electronic/steric properties, brought little influence on the catalytic activities as well as the cis‐1,4‐stereoselectivities of the catalytic system, giving cis‐1,4‐enriched polybutadienes with comparable yields. Furthermore, the presence of such a concentration of N‐donor also brought little influence on the coordinative chain transfer polymerization behaviors of the system, giving narrowly distributed polybutadiene products in a well‐controlled manner. Nevertheless, further increasing the concentration of N‐donors to >1% eventually led to a gradually decreased polymer yields due to the poison of the corresponding active species, and the obtained catalytic efficiencies were highly dependent on the types of N‐donors. The influence of the N‐donor on other parameters of the products, that is, molecular weights, polydispersities, and so forth, were also investigated, and the specific reasons were proposed.