Allenes polymerisation

Various monocomponent catalysts based on nickel compounds, such as Ni(All)2, Ni(All)Cl, Ni(All)OCOCF3 and Ni(Cod)2, have been used for the polymerisation of allene crystalline polymers of rather high molecular weight were yielded, but they were characterised by lower structural regularity as a result of diads made up of 1,2- and 2,1-linked monomeric units [438,441, 442]. Complexes of other transition metals, especially m-Rh(CO)2ClPPh3, Co(A11)3, Co2(CO)8 (in hydrocarbon solutions) and Pd complexes (in acetic acid solutions) are also active in allene polymerisation [241]. 

Chapter on Comparison of Mechanisms, P.E.M. Allen and P.H. Plesch in Chemistry of Cationic Polymerisation, Ed., P.H. Plesch, Pergamon, London, 1963. 

Stretch, C., and G. Allen Anionic polymerisation of styrene. Proc. Chem. Soc. (London), p. 399. 

Coordination polymerisation via re complexes comprises polymerisation and copolymerisation processes with transition metal-based catalysts of unsaturated hydrocarbon monomers such as olefins [11-19], vinylaromatic monomers such as styrene [13, 20, 21], conjugated dienes [22-29], cycloolefins [30-39] and alkynes [39-45]. The coordination polymerisation of olefins concerns mostly ethylene, propylene and higher a-olefins [46], although polymerisation of cumulated diolefins (allenes) [47, 48], isomerisation 2, co-polymerisation of a-olefins [49], isomerisation 1,2-polymerisation of /i-olcfins [50, 51] and cyclopolymerisation of non-conjugated a, eo-diolefins [52, 53] are also included among coordination polymerisations involving re complex formation. 

The polymerisation of allene (1,2-propadiene), the simplest cumulene, is of interest not least because polyallene can be considered to be a versatile intermediate polymer blank , if formed with the chemical structure resulting from polymerisation by the scheme... 

Allene has been polymerised to high molecular weight linear polymers by various Ziegler-Natta catalysts based on compounds of such transition metals as Ti, V, Cr, Mn, Fe, Co and Ni as precursors and alkylaluminium compounds as activators [439-441], Crystalline and amorphous polymers have been produced, in various proportions, with each of the catalysts used. The crystalline polymers consist predominantly of 1,2-linked (head-to-tail) monomeric units formed by insertion polymerisation as in scheme (68), but some regioirregular-ities resulting from the 2,1-insertion, leading to head-to-head and tail-to-tail arrangements, may be present in the polymer chain ... 

Substituted allenes undergo polymerisation to linear polymers in the presence of both Ziegler-Natta catalysts, e.g. VOCl3 Al(i-Bu)3 [440], and monometallic complexes such as Ni complexes [442], Amorphous polymers consisting of 1,2-linked monomeric units (predominant) and 2,3-linked monomeric units have been obtained from 1,2-butadiene (H2C=C=CHCH3) ... 

By contrast, anionic polymerisation of hexafluoro-2-butyne (see Section IIB) proceeds rapidly because elimination of fluoride ion from the propagating anion is difficult, in that it would require the formation of allenes. 

Reactions and catalytic action of metal complexes. Complexes of allene and acetylene and tbeir catalytic polymerisation Tbe cyclisation of alkynes and tbeir derivatives... 

It is a weaker base than Me2NH (pK 10.87) but is caustic to the skin. It should not be inhaled, causes inflammation of the eyes, nose and throat, and one may become sensitized to it. It is soluble in H2O, has an ammoniacal smell and reacts with CO2. Pure aziridine is comparatively stable but polymerises in the presence of traces of H2O and is occasionally explosive in the presence of acids. CO2 is sufficiently acidic to cause polymerisation (forms linear polymers) which is not free radical promoted. It is stable in the presence of bases. The violet 2 1 Cu complex crystallises from EtOH containing a few drops of aziridine and adding Et20, and has m 142°(dec). The picrate has m 142°. [O Rourke et al. J Am Chem Soc 78 2159 1956.] It has also been dried over BaO and has been distilled from sodium under nitrogen. [Allen et al. Org Synth Coll Vol IV 433 1963, Beilstein 20 III/IV 1.] TOXIC. 

Rendiconti della Classe di Scienze fisiche, matematiche e natural , Serie VIII, Vol. 26, Accademia nazionale dei Lincei, Roma - P. E. M. Allen and C. R. Patrick Kinetics and Mechanisms of Polymerisation Reactions, Ellis Horwood Limited, Chichester 1974 - Academic Press, Inc., New York - Royal Society of Chemistry, Chem. Commun. London - Royal Society s Proceedings, London j - La Chimica e I industria, Milano Marcel Dekker, Inc., New York - W. J. Bailey... 

S. Penczek, P. Kubisa, Cationic Ringopening Polymerisation Ethers, in Comprehensive Polymer Science, edited by G. Allen, III, 751-786 (Pergamon Press, Oxford, 1989). 

Gipstein, E., Prime, R. B., and Allen, R., The effect of pressure on the polymerisation cure of acrylate methacrylate copolymers, NATAS, Paper 113 (1991). 

P. E. M. Allen and C. R. Patrick, Kinetics and Mechanisms of Polymerisation Reactions, Ellis Horwood, London, 1974. 

The extreme readiness with which tetrafluoroallene homopolymerises has prevented a study of the orientation of free-radical attack on the allenic system. Perfluoropenta-1,2-diene, however, does not polymerise readily, and so its photochemical chlorination and hydrobromination have been studied. ... 

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