Iron catalysts olefin polymerization

Oxalic acid Oxalic acid dihydrate catalyst, nylon Manganese acetate (ous) catalyst, olefin isomerization Iron pentacarbonyl catalyst, olefin polymerization Acetylacetone Ammonium lactate Chromium carbonyl Chromium chloride (ic) Ethylacetoacetate... 

Allison, M. and Bennet, A., Novel, Highly Active Iron and Cobalt Catalysts for Olefin Polymerization, CHEMTECH, July, 1999, pp. 24-28. 

The Ziegler-Natta catalyst 2,6-diacetylpyridinebisiron(II) chlorotrimethylalu-minium, (I), and procatalyst 2,4- [N-(2,6-dimethylphenyl)]phenylimidoyl 6-methyl pyrimidine iron dichloride, (11), were prepared by Kimberley [1] and Gibson [2], respectively, and used as high-activity 1-olefin polymerization catalysts. 

For example transition metal such as M0O3 and Cr203, are good catalysts for polymerization of olefins a mixture of copper on chromium oxides, called copper chromite, is used for hydrogenation and, a mixture of iron and molybdenum oxide, called iron molybdate, is used for formaldehyde formation from methanol. 

The reader is referred to a series of reviews for more general overviews of postmetallocene a-olefin polymerization catalysts [8-12], while recent reviews relating to the versatility of 2,6-bis(imino)pyridines and to iron- and cobalt-based catalysis itself have also been documented [13-15]. 

The majority of polyolefins is produced with titanium (Zeigler catalysts) and zirconium (metallocene catalysts) or by a fiee radical process Oow-density polyethylene (LDPE)). Recently, late transition metals (LTMs), in particular nickel and palladium [10, 11], and iron and cobalt, are seeing a renewed interest as olefin polymerization catalysts [12, 13]. 

The discovery of a highly active family of catalysts based on iron, a metal that had no previous track record in this field, has highlighted the possibilities of further new catalyst discoveries. The search for new catalysts be restricted to metals that have a history of giving polymerization-active centers was no longer needed. The LTMs especially are likely to provide fertile ground for future development, and the greater functional group tolerance of the LTMs also offers the attractive prospect of polar co-monomer incorporation. A relatively small amount of functionality can dramatically transform the adhesion and wettability properties of polyolefins more heavily functionalized products offer the prospect of materials with totally new properties and performance parameters. It is clear that, for olefin polymerization catalysis, the process of catalyst discovery and development is far from over. 

G. Britovsek, V. Gibson, B. Kimberiey, P. Maddox, S. MeTavish, G. Solan, A. White, D. Williams, Novel olefin polymerization catalysts based on iron and cobalt. Chem. Commun. 7, 849-850 (1998)... 

Another new catalyst generation based on iron and cobalt. The direct iron analogs of the nickel-diimine catalysts derived from structures (25) and (26) did not seem to be very active in olefin polymerization at all. The electronic and steric structure analysis shows why the nickel d -system favors a square planar coordination sphere but the iron d -system favors a tetrahedral one. It is very likely that these tetrahedral coordination sites are not available for olefin insertion, and hence no polymerization can take place. 

Not only palladium, but many more non-metallocene late (and early) transition metal catalysts for the coordination polymerization of ethene and 1-olefins were reported [11]. Among the most significant findings in this area are the disclosures of novel highly active and versatile catalysts based on (i) bidentate diimine [N,N] nickel and palladium complexes [12], (ii) tridentate 2,6-bis(imino)pyridyl [N,N,N] iron and cobalt complexes [13], and (iii) bidentate salicyl imine [N,O] nickel complexes [14]. 

---