Ethylene/norbornene copolymerisation

Yoshida, Y, Saito, J., Mitani, M. et al. (2002) Living ethylene/norbornene copolymerisation catalyzed by titanium complexes having two pyrrolide-imine chelate ligands. Chemical Communications, 1298-1299. 

Random ethylene/propylene copolymers are amorphous and represent an interesting class of synthetic elastomers. The introduction of double bonds, useful for sulphur vulcanisation in the copolymer, can be achieved by copolymerisation of ethylene and propylene with non-conjugated dienes containing only one double bond capable of insertion for instance, 1,4-hexadiene, dicy-clopentadiene and 5-ethylidene-2-norbornene (endocyclic double bond)... 

While ethylene is vastly more reactive than cyclopentene in copolymerisation with the (IndCH2)2ZrCl2 [AI(Mc)0]x. catalyst (relative reactivity ratio of ethylene r = 80 300), norbornene is quite readily incorporated, with... 

Metallocene catalysts show low r values, which allows easy incorporation of bulky cycloolefins into the growing copolymer chain. Surprisingly, the ethylene reactivity ratio in copolymerisation with cyclopentene in the presence of a (ThindCH2)2ZrCl2-based catalyst (r = 2.2) and in copolymerisation with norbornene in the presence of catalysts characterised by Cs and Ci symmetry (ri 3.4 and 3.1 respectively) is considerably lower than that for the copolymerisation of ethylene with propylene (r = 6.6 at 37 °C). Various catalysts produce copolymers of structures that are between statistical and alternating [468]. 

Ethylene has also been copolymerised successfully with substituted polycyclic olefins, such as 5-phenyl-2-norbornene (endo/exo = 2.3 1) and 2-phenyldimetha-nooctahydronaphthalene (endo/exo = 2.3 1), in the presence of (/-symmetric... 

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