16262-93-4Relevant articles and documents
Reaction of oxygen with γ,δ-ethylenic phenylhydrazones. Model reaction of end-group behavior in phenylhydrazine-accelerated oxidation of natural rubber
Hamdaoui, Azeddine El,Reyx, Daniele,Campistron, Irene
, p. 406 - 416 (2007/10/02)
An accurate definition of terminal groups of chains in the liquid polymers obtained by the phenylhydrazine-accelerated oxidation of natural rubber is needed.The object of the work was to use model molecules to explore the behavior of γ,δ-ethylenic methylketone phenylhydrazone end-groups in oxidation conditions.We have investigated the synthesis and characterization of models of these hypothetical end-groups, methylketones and phenones 1, their phenylhydrazones 2, the α-(phenyldiazenyl)hydroperoxides 3 resulting from reaction of 2 with oxygen, and the α-(phenyldiazenyl)alcohols 4 as characteristic derivatives of 3 or as models of possible reduced structures in oxidized liquid natural rubber.Three original syntheses of γ,δ-ethylenic ketones were carried out.In the case of γ,δ-ethylenic phenylhydrazones, the oxidation led to the expected α-(phenyldiazenyl)hydroperoxides and to epoxide derivatives of α-(phenyldiazenyl)alcohols 5 and ketones 6.An intramolecular mechanism is proposed.The results are used to predict the possibilities of identification of the corresponding end-groups in liquid rubbers produced in this way. - Key words: accelerated oxidation / natural rubber / phenylhydrazine / γ,δ-ethylenic ketone / γ,δ-ethylenic phenylhydrazone / α-(phenyldiazenyl)hydroperoxide / α-(phenyldiazenyl)alcohol / γ,δ-epoxyketone
