High-performance olefin polymerization catalysts discovered on the basis of a new catalyst design concept

Abstract

This critical review highlights the "ligand oriented catalyst design concept", a new catalyst design concept for olefin polymerization that has led to the development of high-activity catalysts. The concept has created a series of highly active ethylene polymerization catalysts, many of which show high activities comparable to those of group 4 metallocene catalysts. Moreover, these catalysts display unique polymerization catalysis to produce a wide variety of polymers that possess unprecedented molecular architectures that are either difficult or impossible to achieve using conventional catalysts (98 references).

Cationic polymerization of isobutyl vinyl ether using alcohols both as cationogen and catalyst‐modifying reagent: Effect of Lewis acids and alcohols on living nature

“…For NbCl 5 , stock solution in the mixture of dichloromethane and ethyl acetate was prepared from commercial anhydrous NbCl 5 (Strem; 99.99%). For ZrCl 4 , stock solution in ethyl acetate was prepared from commercial ZrCl 4 (Aldrich; 99.99%). Commercially available SnCl 4 (Aldrich; 1.0 M solution in dichloromethane) was used without further purification.…”

“…Catalysts inducing slow exchanges between the dormant and active species or producing highly active propagating species, or ''free ion'' species, 7 should give uncontrolled portions with high MW. Such uncontrolled portion can be produced despite the low activity of the catalyst, as in the case of polymerization using SiCl 4 or SbCl 3 without additives in conjunction with IBVEHCl. 8 In addition, the surplus diol may have induced undesired reactions such as coupling, that is, reactions (termination and/or transfer) of the two hydroxy groups with the propagating chains.…”

“…5,6 Living cationic polymerization of vinyl monomers is a Lewis acid-mediated reaction. 7 In contrast to the aforementioned well-designed catalysts, simple metal halides, such as TiCl 4 and SnCl 4 , have been used for controlled reactions in combination with suitable additives and cationogens. Our group recently demonstrated that, in addition to the conventional metal chlorides, a variety of metal chlorides can induce living cationic polymerization of vinyl ether (VE) in conjunction with a VE-HCl adduct or methanol as a cationogen.…”

“…Subtle differences in the substituents of ligands can lead to a great improvement in catalytic activity and almost complete control of the stereoregularity of the product polymers. [1][2][3][4] Transition metal-catalyzed living radical polymerization, or ATRP, using metal complexes whose redox potentials are suitably adjusted by various ligands is another excellent example of ligand design. 5,6 Living cationic polymerization of vinyl monomers is a Lewis acid-mediated reaction.…”

Research Progress of Pre - transition Metal Olefin Polymerization Catalyst for Salicylaldehyde Imine

“…Finding shows that the steric hindrance eff ect of the ligand phenol ring and the imine nitrogen had diff erent spatial stereocomplexes (Fig.1), and the catalytic properties were directly affected by the different electronegativity of the substituents. The steric hindrance effect and the electron effect of the ligand substituents on the catalytic activity center play an important role in the regulation of catalytic performance [6]. The present research work has proved that the most signifi cant eff ect on the catalytic performance of salicylaldehyde imine ligand structure is phenoxy ortho substituents, and its steric hindrance eff ect directly aff ects the catalytic activity.…”