Neodymium catalysts for polymerization of dienes, vinyl monomers, and ε-caprolactone

Abstract

This review discusses various neodymium catalysts for stereospecific polymerization of dienes, vinyl monomers, and ε-caprolactone.

Polymerization of α-olefins and their copolymerization with ethylene by half-sandwich scandium catalysts with an N-heterocyclic carbene ligand

“…The copolymerization of ethylene with 1-octene or 1-dodecene using 3b also took place with high activity (Table 3, runs [19][20][21][22][23][24][25][26][27][28]. The resulting copolymers possessed controllable 1-octene and 1-dodecene content (3.0-51.8 mol%) and high molecular weight (M n = 10.8 × 10 4 -41.8 × 10 4 ).…”

“…5,8,9,[19][20][21][22] Rare-earth metal catalysts have attracted a great deal of attention during the past two decades due to their unique catalytic performance in a variety of polymerization reactions of compounds such as ethylene, styrene, 1,3-conjugated dienes, polar monomers, etc. [23][24][25][26][27][28] However, most of these rare-earth metal catalysts usually show low activity or an irreversible chain termination reaction (such as β-H elimination) in α-olefin polymerization, only affording polymers with low molecular weight. [29][30][31][32][33][34][35][36] Recently, by the use of some post-metallocene scandium complexes, [37][38][39] poly(α-olefins) with high molecular weight can be obtained; however, the copolymers of α-olefins and ethylene could not still be obtained.…”

Pyridine-amido aluminum catalyst precursors for 1,3-butadiene transition-metal-free stereospecific polymerization

“…Synthesis of pyridine-2-C(Me)vN(Ph) (1). Aniline (12 g, 128.9 mmol), 2-acetylpyridine (14.2 g, 117.2 mmol), toluene (150 mL) and p-toluenesulfonic acid monohydrate (0.1 g, 5.3 mmol) were added to a flask adapted with a Dean-Stark trap.…”

“…Stereospecific polymerization of 1,3-butadiene has attracted considerable attention in the past decades. [1][2][3][4] Since their initial discovery by pioneers such as Karl Ziegler and Giulio Natta, transition metals have played an irreplaceable role in stereotactic polymerization. [5][6][7] Ziegler-Natta catalysts based on transition metal compounds, such as Ti, V, Cr, Mo, Fe, Co, and Ni, have emerged successively, and they can be used to synthesize polybutadiene with controllable microstructures.…”

Towards full recyclability of end-of-life tires: Challenges and opportunities

“…Synthetic cis-PBR is produced by solution polymerization of butadiene in the presence of Ziegler-Natta catalysts with different catalyst atoms, e.g., neodymium, cobalt, and titanium. Currently, neodymium presents the best performance with at least 98% of 1,4-cis and low polydispersity (2.9-3.2) in the final product (Wang, H. et al, 2021). PBR has the lowest Tg among hydrocarbon rubbers and excellent elastic properties at low temperatures (Mansourkhaki et al, 2020).…”