Synthesis of Ti, Zr, and Hf complexes with a new tetra-azane ligand by one-pot HCl-elimination and their properties as catalysts for production of UHMWPE

Abstract

The first example for the HCl-elimination reaction being applied in the attachment of an amido-containing ligand to Zr and Hf.

Recent advancements in N-ligated group 4 molecular catalysts for the (co)polymerization of ethylene

“…This finding was attributed to either an increased barrier to monomer insertion with hafnium [173] or to less efficient activation by MAO [174,175]. Mu and coworkers disclosed a series of titanium, zirconium and hafnium complexes 65 -67 [176], bearing dianionic tetradentate anilido-imine ligands (Figure 25). In the presence of MAO and/or AliBu3/Ph3C+B(C6F5)4-, these complexes showed moderate catalytic activities and good thermostability for ethylene polymerization.…”

Synthesis of ultrahigh-molecular-weight ethylene/1-octene copolymers with salalen titanium(iv) complexes activated by methyaluminoxane

“…26,27 Salalen type complexes exhibit amazing catalytic performance on various reactions like ring-opening polymerization, asymmetric oxidations, epoxide-CO 2 polymerization and a-olen homopolymerization. [28][29][30][31][32][33][34][35][36][37][38][39] But to the best of our knowledge, there are few literature has been reported using salalen type complexes on the copolymerization of ethylene with long chain a-olen. Our research group previously synthesized two types of salalen titanium(IV) complexes (Scheme 1) and successfully applied them to produce ultrahigh-molecular-weight ethylene.…”

Remarkable Promotion Effect of Sulfation over the SiO2‐Supported Vanadium‐Oxide‐Based Catalysts for UHMWPE

“…In recent years, the versatile single‐site catalysts, because of their tailor‐made characteristics, have been widely reported for the synthesis of UHMWPE, but well‐designed structures are necessary, and large steric hindrance of the molecular catalysts or low polymerization temperature ( T p ) is seemed more favored. The group of Alt investigated the polymerization results of ≈100 metallocene catalysts, finding the MW of most PEs synthesized was well below the critical value of 10 6 g mol −1 .…”