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

Abstract

Evaluation 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.

Neodymium-Mediated Coordinative Chain Transfer Polymerization of Isoprene in the Presence of External Donors

“…By contrast, a CCTP strategy can overcome such a shortage, because it demonstrates a highly atom-economic characteristic, that is, one Nd atom can produce multiple polydienyl chains, which therefore serves as an effective strategy to reduce the cost of a Nd-based precatalyst [27][28][29][30][31][32][33][34][35][36][37][38]. Based on this consideration, much of our recent research has looked to explore any factors that could have an influence on CCTP behaviors [28][29][30]34,36,39]. Of all the possible factors, heteroatom-based external donors are of great importance, because they are often used to disassociate the clustered structure of the neodymium precatalyst or to facilitate the formation of active species [40][41][42][43][44][45].…”