Zeigler catalyst

Natta, a consultant for the Montecatini company of Milan, Italy, applied the Zeigler catalysts to other vinyl monomers such as propylene and found that the polymers were of higher density, higher melting, and more linear than those produced by the then classical techniques such as free-radical-initiated polymerization. Ziegler and Natta shared the Nobel Prize in 1963 for their efforts in the production of vinyl polymers using what we know today as solid state stereoregulating catalysts. 

Discuss advantages of the soluble stereoregulating catalysts in comparison with the Natta-Zeigler catalysts. 

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]. 

Phillips supported chromium (II) catalyst, the most commonly used for high density polyethylene (HDPE) manufacture, possibly behaves in a similar manner, but the olefin insertion reaction is faster by several orders of magnitude. In the original Zeigler catalyst systems for HDPE, an aluminium alkyl is used to reductively alkylate the primary component, most frequently a titanium compound, to give the true catalytic species. 

Zambelli A, Proto A, Lmigo P (1995) In Fink G, MiUhaupt R, Brintzinger HH (eds) Zeigler catalysts recent scientific irmovations and technological improvements. Springer, Berlin, pp 217-235... 

Billmeyer, E. W., Jr., Textbook of Polymer Science, Wiley, New York, 292,1962. Transition metal-catalyzed polymerization (Zeigler catalyst) [14]... 

Zeigler-Natta catalysts Zein coatings Zeisses salt Zelan... 

Similar stability and reactivity have also been observed for bridged-Cp systems. The catalyticaHy active (CH2)2Si(C (CH2)4)2ThR2, where R = Cl [89597-06-8] alkyl, CH2CgH [89597-10A] aryls, or H [89597-11-5], Similar to Group 4 transition-metal Zeigler-Natta catalysts, stable cationic Th(IV) species, eg, [Cp 2ThCH2] [108834-69-17, have been isolated with a host of noncoordinatiag/nonreactive anions. MetaHacycle formation has also been... 

J. Boor, Jr., Zeigler-Natta Catalysts andPolymeri tions, Academic Press, Inc., New York, 1979. 

A polymer-bound hindered amine light stabilizer [P-HALS] has been synthesized by terminating the living anionic polymerization of isoprene with 4(2,3-epoxy pro-poxy)-1,2,2,6,6-pentamethylpiperidine followed by hydrogenation of the resulting polymer to E-P copolymer using Zeigler type catalyst [40] ... 

To carry out this process ethylene gas is passed through a fluidised bed column that is filled with Zeigler-Natta catalyst... 

While it was possible to produce sPP, employing the Zeigler-Natta solid systems, commercial sPP has only recently become commercial through the use of the soluble metallocene catalysts. These materials have a similar Tg as iPP, but they have a different balance between stiffness and toughness. 

The polymerization of ethylene via the Zeigler-Natta process is extremely important commericially and serves as an excellent example of the role of the a-v rearrangement in catalysis (14). The catalyst in this... 

Albizzati, E., Giannini, U., Morini, G., Smith, C. A. and Zeigler, R. C., Advances in Propylene Polymerization with MgCl2-supported Catalysts , in Ziegler Catalysts, Springer-Verlag, Berlin, 1995, pp. 413-425. 

A few attempts have been made to copolymerize vinylcyclohexane with other monomers using coordination-type polymerization catalysts. The successful copolymerization of styrene and vinylcyclohexane [50] with a Zeigler-type catalyst has been reported. The copolymerization of the closely related monomer 4-vinylcyclohexene with ethylene using a Zr-based metallocene and methy-lalumoxane activator has been described [51]. 

Volume 15 deals with those polymerization processes which do not involve free radicals as intermediates. Chapters 1 and 2 cover homogeneous anionic and cationic polymerization, respectively, and Chapter 3 polymerizations initiated by Zeigler-Natta and related organometallic catalysts. Chapters 4, 5 and 6 deal with the polymerization of cyclic ethers and sulphides, of aldehydes and of lactams, respectively. Finally, in Chapter 7 polycondensation reactions, and in Chapter 8 the polymerization of AT-carboxy-a-amino acid anhydrides, are discussed. 

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