Syndiotactic polypropylene synthesis

Tian J, Coates GW, Development of a diversity-based approach for the discovery of stereoselective polymerization catalysts Identification of a catalyst for the synthesis of syndiotactic polypropylene, Angew. Chem. Int. Ed. Eng., 39 3626-3629, 2000. 

Iodine readily reacts with polymers bound to coordination centres, yielding macromolecules containing iodide end groups. The C—I bond can react with silver salts of superacids yielding carbocations essentially in the sense of the last steps of eqn. (32). Doi et al. [251, 252] have used this reaction for the synthesis of the copolymer poly(propene)-Mocfc-poly(tetramethylene oxide) with blocks of syndiotactic polypropylene. 

The Ziegler-Natta catalysts that are used most industrially are solids that are suspended in the reaction medium. The polymerization reaction that is favored depends on the catalyst components and on their state of aggregation and other details of their preparation. Heterogeneous catalytic systems appear to be necessary for the production of isotactic polyolefins, but soluble catalysts have been used for the synthesis of polyethylene and syndiotactic polypropylene. 

A further breakthrough was the synthesis of enantiomeric sterorigid ansa-metallocenes by Brintzinger and co-workers [33] and the discovery by Ewen [34] that such racemic metallocene/methylalumoxane systems generate isotactic polypropylene. It was further found that the metallocene structure determines the polymer structure [35-37]. Again, with these compounds polyolefins such as syndiotactic polypropylene become available on a large scale [38]. Indeed, metallocene/methylalumoxane catalysts offer new prospects for olefin oligomers and polymers [39 2],... 

Corradini, P Guerra, G Pucciariello, R. New model of the origin of the stereospecificity in the synthesis of syndiotactic polypropylene. Macromolecules 1985,18, 2030-2034. 

Cai, Z.G., Nakayama, Y, and Shiono, T. (2006) Living random copolymerization of propylene and norbomene with anm-fluorenylamidodimethyltitanium complex Synthesis of novel syndiotactic polypropylene-Wock-poly(propyl-... 

Cherian, A.E., Lobkovsky, E.B., and Coates, G.W. (2005a) Synthesis of allyl-terminated syndiotactic polypropylene macromonomers for the synthesis of branched polyolefins. Macromolecules, 38,6259-6268. 

Lee J-Y, Lin C-J, Lo C-T, Tsai J-C, Chen W-C (2013) Synthesis, morphology, and field-effect transistor characteristics of crystalline diblock copolymers consisted of poly (3-hexylthiophene) and syndiotactic polypropylene. Macromolecules 46 3005-3014... 

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