Ring opening polymerization cycloolefins

Ring-Opening Polymerization. Ring-opening polymerization of cycloolefins in the presence of tungsten- or molybdenum-based catalysts proceeds by a metathesis mechanism (67,68). 

G. DalTasta and G. Motroni, Site of ring cleavage in the ring-opening polymerization of low strained cycloolefins, Eur. Polym.., 7(6) 707-716,1971. 

K. Ohkita, T. Imamura, and N. Oshima, Cycloolefin copolymer formed by ring-opening polymerization, process for producing the same, and optical material, US Patent 7056999, assigned to JSR Corporation (Tokyo, JP), June 6,2006. 

Ivin KJ (1983) Olefin metathesis, Academic, New York Dragutan V, Balaban AT, Dinonie M (1985) Olefin metathesis and ring-opening polymerization of cycloolefins, Wiley, New York... 

Metathesis of Cycloolefins. The same general catalysts which promote the ring-opening polymerization of cycloolefins are also effective in the olefin metathesis reaction in which acyclic internal olefins undergo a unique redistribution process (1, 2, 5, 6). 

N. Calderon, Ring-opening polymerization of cycloolefins, J. Macromol. Sci. (Revs.) C7, 105 (1972). 

Poly(alkenamers) are produced by ring-opening polymerization of cycloolefins with metathesis catalysts (see Chapter 19). The industrially used name for this class of compounds is based on a lUPAC nomenclature that has since been superceded. These compounds are classified as poly( 1-alkenylenes) according to present lUPAC nomenclature. Poly(pentenamers) and poly-(octenamers) are presently being developed. 

Dragutan, A., Balaban AT. and Dimonie, M. (1985) Olefin Metathesis and Ring-Opening Polymerization of Cycloolefins, Editura Academiei Bucuresti and John Wiley and Sons Ltd, Chichester. 

Analogously, the ring-opening polymerization of cycloolefins can result in trans- or cA-polyalkenamers via a trans or cis route [5, 7, 14] [Eq. (3)]. 

There are several types of Ziegler-Natta and ROMP catalysts employed for cycloolefin polymerization, the majority of them being derived from transition metal salts and organometallic compounds [4-7]. These types are grouped into unicomponent, binary, ternary, and multicomponent catalytic systems as a function of the presence or absence of the organometallic cocatalyst or other additives, each of them being differentiated on the catalyst composition and selectivity toward vinylic or ring-opened polymerization. 

Carbene complexes of tungsten, molybdenum or rhenium initiate the ring-opening polymerization of cycloolefins to polyalkenamers. Thus, Ph2C= W(CO)5 (1) polymerizes cyclobutene, 1-methylcyclo-butene, cyclopentene, cycloheptene, cyclooctene and norbornene while Ph(MeO)C=W(CO)5 (2) polymerizes cyclobutene and norbornene to highly stereospecific polyalkenamers [28]. 

Titanacyclobutanes (6 and 7) and tantallacyclobutanes (8 and 9) showed to be a new class of active catalysts for Uving ring-opening polymerization of cycloolefins [31, 32]. 

A different kinetic behavior is encountered in the ring-opening polymerization of cycloolefins using ROMP catalysts [6]. This process must be complex to accommodate the well-known difficulties stemming from the treatment of Ziegler-Natta systems [186]. The main kinetic data come from homogeneous catalytic systems involving the metathesis polymerization... 

There is strong evidence that the ring-opening polymerization of cycloolefins provides a convenient approach for the synthesis of poiyaikenamers with high trans or cis content [2, 3]. Except for polyhexen-amer, poiyaikenamers of predominantly trans structure have been obtained from cyclobutene to cyclododecene, and poiyaikenamers of predominantly cis structure from cyclobutene to cyclooctene. In addition, poiyaikenamers of high steric purity have been obtained from norbomene and its derivatives or from other bicyclic and polycyclic olefins. 

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