Controlled/living radical polymerization: Features, developments, and perspectives

B. Anionic Ligands 302 IX. Group 9 Catalysts 302 X. Group 10 Catalysts 303 A. Neutral Ligands 303 1. R-Diimine and Related Ligands 303 2. Other Neutral Nitrogen-Based Ligands 304 3. Chelating Phosphorus-Based Ligands 304 B. Monoanionic Ligands 305 1. [PO] Chelates 305 2. [NO] Chelates 306 3. Other Monoanionic Ligands 306 4. Carbon-Based Ligands 306 XI. Group 11 Catalysts 307 XII. Group 12 Catalysts 307 XIII. Group 13 Catalysts 307 XIV. Summary and Outlook 308 XV. Glossary 308 XVI. References 308

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Advances in non-metallocene olefin polymerization catalysis.

Current status and future perspectives in atom transfer radical polymerization (ATRP) are presented. Special emphasis is placed on mechanistic understanding of ATRP, recent synthetic and process development, and new controlled polymer architectures enabled by ATRP. New hybrid materials based on organic/inorganic systems and natural/synthetic polymers are presented. Some current and forthcoming applications are described.

Atom Transfer Radical Polymerization (ATRP): Current Status and Future Perspectives

Schiff base ligands are considered “privileged ligands” because they are easily prepared by the condensation between aldehydes and imines. Stereogenic centres or other elements of chirality (planes, axes) can be introduced in the synthetic design. Schiff base ligands are able to coordinate many different metals, and to stabilize them in various oxidation states, enabling the use of Schiff base metal complexes for a large variety of useful catalytic transformations. Practical guidelines for the preparation and use of different Schiff base metal complexes in the field of catalytic transformations are discussed in this tutorial review.

Metal–Salen Schiff base complexes in catalysis: practical aspects

Elastic substantially linear olefin polymers are disclosed which have processability similar to highly branched low density polyethylene (LDPE), but the strength and toughness of linear low density polyethylene (LLDPE). The polymers have processing indices (PI's) less than or equal to 70 percent of those of a comparative linear olefin polymer and a critical shear rate at onset of surface melt fracture of at least 50 percent greater than the critical shear rate at the onset of surface melt fracture of a traditional linear olefin polymer at about the same I2 and Mw?Mn. The novel polymers can also have from 0.01 to 3 long chain branches/1000 carbons along the polymer backbone and have higher low/zero shear viscosity and lower high shear viscosity than comparative linear olefin polymers. The novel polymers can also be characterized as having a melt flow ratio, I10/I2, » 5.63, a molecular weight distribution, Mw/Mn, defined by the equation: Mw/Mn « (I10/I2) - 4.63, and a critical shear stress at onset of gross melt fracture greater than 4 x 10?6? dyne/cm2.

Elastic substantially linear olefin polymers

Seven titanium complexes bearing fluorine-containing phenoxy−imine chelate ligands, TiCl2{η2-1-[C(H)NR]-2-O-3-tBu-C6H3}2 [R = 2,3,4,5,6-pentafluorophenyl (1), R = 2,4,6-trifluorophenyl (2), R = 2,6-difluorophenyl (3), R = 2-fluorophenyl (4), R = 3,4,5-trifluorophenyl (5), R = 3,5-difluorophenyl (6), R = 4-fluorophenyl (7)], were synthesized from the lithium salt of the requisite ligand and TiCl4 in good yields (22%−76%). X-ray analysis revealed that the complexes 1 and 3 adopt a distorted octahedral structure in which the two phenoxy oxygens are situated in the trans-position while the two imine nitrogens and the two chlorine atoms are located cis to one another, the same spatial disposition as that for the corresponding nonfluorinated complex. Although the Ti−O, Ti−N, and Ti−Cl bond distances for complexes 1 and 3 are very similar to those for the nonfluorinated complex, the bond angles between the ligands (e.g., O−Ti−O, N−Ti−N, and Cl−Ti−Cl) and the Ti−N−C−C torsion angles involving the phenyl on the im...

Living Polymerization of Ethylene Catalyzed by Titanium Complexes Having Fluorine-Containing Phenoxy−Imine Chelate Ligands

This paper reviews a new family of olefin polymerization catalysts The catalysts, named FI catalysts, are based on non-symmetrical phenoxyimine chelate ligands combined with group 4 transition metals and were developed using “ligand-oriented catalyst design” FI catalysts display very high ethylene polymerization activities under mild conditions The highest activity exhibited by a zirconium FI catalyst reached an astonishing catalyst turnover frequency (TOF) of 64,900 s –1 atm –1, which is two orders of magnitude greater than that seen with Cp2ZrCl2 under the same conditions In addition, titanium FI catalysts with fluorinated ligands promote exceptionally high-speed, living ethylene polymerization and can produce monodisperse high molecular weight polyethylenes (Mw/Mn 400,000) at 50 °C The maximum TOF, 24,500 min –1 atm –1, is three orders of magnitude greater than those for known living ethylene polymerization catalysts Moreover, the fluorinated FI catalysts promote stereospecific room-temperature living polymerization of propylene to provide highly syndiotactic monodisperse polypropylene (max [rr] 98%) The versatility of the FI catalysts allows for the creation of new polymers which are difficult or impossible to prepare using group 4 metallocene catalysts For example, it is possible to prepare low molecular weight (Mv∼103) polyethylene or poly(ethylene-co-propylene) with olefinic end groups, ultra-high molecular weight polyethylene or poly(ethylene-co-propylene), high molecular weight poly(1-hexene) with atactic structures including frequent regioerrors, monodisperse poly(ethylene-co-propylene) with various propylene contents, and a number of polyolefin block copolymers [eg, polyethylene-b-poly(ethylene-co-propylene), syndiotactic polypropylene-b-poly(ethylene-co-propylene), polyethylene-b-poly(ethylene-co-propylene)-b-syndiotactic polypropylene] These unique polymers are anticipated to possess novel material properties and uses

FI Catalysts: A New Family of High Performance Catalysts for Olefin Polymerization

A process for polymerizing olefin which comprises using a catalyst comprising a transition metal catalyst component, an aluminoxane component, and an organo-aluminum component. In this process, a catalyst containing a reduced amount of the above-described aluminoxane is used to attain an excellent polymerization activity. This process affords a polymer with a narrow molecular weight distribution, while it affords an olefin copolymer having a narrow molecular weight distribution and a narrow composition distribution in a copolymerization of two or more olefins.

Process for polymerizing olefins

Living Polymerization of Ethylene with a Titanium Complex Containing Two Phenoxy-Imine Chelate Ligands.

PURPOSE:To polymerize an olefin in excellent polymerization activity even in a decreased amount of an aluminoxane used, by using a catalyst comprising a specified supported solid catalyst component, an aluminoxane and a specified organoaluminum compound. CONSTITUTION:An olefin is (co)polymerized in the presence of a catalyst formed from a solid catalyst component (A) formed by allowing an inorganic carrier (e.g., SiO2 or Al2O3) to support a Group IV B transition metal compound [e.g., bis(cyclopentadienyl)zirconium dichloride], an aluminoxane (B) [e.g., a compound of formula I or II (wherein R is methyl or the like and m is an integer >=2)] and an organoaluminum compound (c) having a hydrocarbon group other than an n-alkyl group (e.g., triisopropylaluminum). When olefin polymerization, especially, ethylene polymerization or copolymerization of ethylene with an alpha-olefin according to the above process is performed by a slurry polymerization or vapor-phase polymerization process, the catalytic activity is high even in a decreased amount of the aluminoxane used and no adhesion of polymer to the reactor occurs. When this process is applied to the copolymerization of at least two olefins, a copolymer of a narrow MW distribution and a narrow composition distribution can be obtained.

Norio Kashiwa

Papers

Living Polymerization of Ethylene Catalyzed by Titanium Complexes Having Fluorine-Containing Phenoxy−Imine Chelate Ligands

FI Catalysts: A New Family of High Performance Catalysts for Olefin Polymerization

Process for polymerizing olefins

Living Polymerization of Ethylene with a Titanium Complex Containing Two Phenoxy-Imine Chelate Ligands.

Polymerization of olefin