Stereochemistry of propylene polymerization

Zambelli, Adolfo; Tosi, Camillo

doi:10.1007/3-540-06910-0_2

Cited by 73 publications

(32 citation statements)

References 65 publications

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“…The same conclusion has been reached by Zambelli et al on the basis of IR [410] and NMR [411,413] analysis of ethylenepropylene homopolymers and copolymers obtained with syndiospecific catalysts. These authors point out that the type of insertion is conditioned by steric factors: the secondary insertion of a propylene unit is more frequent when the last monomeric unit of the growing chain is propylene, whereas the primary insertion (or 1-2, namely:…”

Section: Insertion Of Monomeric Units -Regiospecijicitysupporting

confidence: 68%

Catalytic Olefin Polymerization

Pasquon

Giannini²

1984

Advances in Comparative and Environmental Physiology

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Section: Insertion Of Monomeric Units -Regiospecijicitysupporting

confidence: 68%

Catalytic Olefin Polymerization

Pasquon

Giannini²

1984

Advances in Comparative and Environmental Physiology

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“…The intensity of the 13 C resonances at 18.0 2 and 18.6 6 (rrrm and rrmr methyl pentads), in comparison with those of the other methyl stereochemical pentads, particularly the rmmr, show that, at least in the first approximation, the stereochemistry of chain propagation is controlled by the (chiral) last unit of the growing chain end. [2,22,23] prepared at -78 8C in heptane with the catalytic system VCl 4 1Al(CH 3 ) 2 Cl-anisole. [16] The NMR spectra reported in this paper (except in Figure 6) have been performed on polymers dissolved in tetrachloroethane-1,2-d 2 at 120 8C.…”

Section: Vanadium Catalysts 3a General Features Of the Homogeneous Camentioning

confidence: 99%

“…[1] Actually, these heterogeneous systems are multi-site catalysts and produce isotactic, syndiotactic and stereoirregular macromolecules [2] simultaneously, although isotactic poly(propylene) is the main reaction product.…”

Section: Introductionmentioning

confidence: 99%

Syndiotactic Polymerization of Propylene: Single-Site Vanadium Catalysts in Comparison with Zirconium and Nickel

Zambelli¹,

Sessa

Grisi

et al. 2001

Macromol. Rapid Commun.

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The syndiotactic‐specific polymerization of propylene can be promoted by single‐site catalysts based on vanadium, nickel and group IV metals. The polymerization mechanisms are reasonably well established for nickel and group IV metals. For vanadium catalysts the polymerization mechanisms reported in the literature are still debatable, since the stereochemistry of the monomer insertion is well known, but the active species have never been isolated. In this paper the mechanisms concerning Ni and group IV metal catalysts are briefly summarized and proposed mechanisms concerning vanadium are compared within one another.

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“…Various mechanisms have been proposed to explain the stereoselectivity of Ziegler-Natta initiators [Boor, 1979;Carrick, 1973;Corradini et al, 1989;Cossee, 1967;Ketley, 1967a,b;Tait and Watkins, 1989;Zambelli and Tosi, 1974]. Most mechanisms contain considerable details that distinguish them from each other but usually cannot be verified.…”

Section: -4a Historical Development Of Ziegler-natta Initiatorsmentioning

confidence: 99%

Stereochemistry of Polymerization

Odian

2004

Principles of Polymerization

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Constitutional (formerly: structural) isomerism is encountered when polymers have the same overall chemical composition (i.e., same molecular formula) but differ in connectivitythe order in which the atoms are connected to each other. Polyacetaldehyde, poly(ethylene oxide), and poly(vinyl alcohol) are constitutional isomers. The first two polymers are CH CH 3 O C H 2 CH OH CH 2 CH 2 O n n Polyacetaldehyde Poly(ethylene oxide) Poly(vinyl alcohol) n obtained from isomeric monomers, acetaldehyde and ethylene oxide. The third is obtained by hydrolysis of poly(vinyl acetate) since vinyl alcohol does not exist (it is the enol form of acetaldehyde). Poly(methyl methacrylate) and poly(ethyl acrylate) are isomeric polymers CH 2 C CH 3 CO 2 CH 3 CH 2 CH CO 2 C 2 H 5 n n Poly (methyl methacrylate) Poly (ethyl acrylate) formed from isomeric monomers. Poly(E-caprolactam) and poly(hexamethylene adipamide) are isomeric even though the monomers are not isomeric. Similarly, the 1 : 1 copolymer of Principles of Polymerization, Fourth Edition.

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Stereochemistry of propylene polymerization

Cited by 73 publications

References 65 publications

Catalytic Olefin Polymerization

Catalytic Olefin Polymerization

Syndiotactic Polymerization of Propylene: Single-Site Vanadium Catalysts in Comparison with Zirconium and Nickel

Stereochemistry of Polymerization

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