A study of the oxidative polyarylation of some napthyl ethers and the properties of the resultant polymers.

The effect of various Lewis acids on the dimerisation and polymerisation of aromatic substrates has been investigated. In the dimerisation of 1-ethoxynaphthalene, to 4,4'-diethoxy-1,1'-binaphthyl, it was found that the catalyst system ferric chloride in nitrobenzene resulted in higher yields than any other catalyst investigated. A variety of novel polymers were prepared by allowing difunctional substrates, containing the 1-naphthyl ether group, to react with ferric chloride in nitrobenzene: [diagram]. A study has been made of the variation of properties of a homologous series of poly (dinaphthyl alkylene ethers): [diagram] with the number of methylene groups in the structure Cm). Melting points, melt viscosities and densities decreased, while impact strength increased with m. The "zig-zag" pattern of change of properties with m diminished as m increased. The dimerisation of 1-ethoxynaphthalene has also been studied kinetically. Initial rates of disappearance of 1-ethoxynaphthalene and appearance of ferrous ion were followed, and an initial rate equation derived: initial rate = k[O] [1-ethoxynaphthalene][O][1/2][FeCl[3]][O]. In experiments with added hydrogen chloride, the initial rate was found to be inversely proportional to the concentration of hydrogen chloride. When either 1-ethoxynaphthalene or its dimer is allowed to react with ferric chloride in nitrobenzene, red or green coloured solutions are formed. As a result of a spectroscopic study of these solutions, it was concluded that three intermediates are involved in the dimerisation, and that the red solutions contain a paramagentic species that can be formed from both substrate and dimer. A reaction mechanism for the dimerisation of 1-ethoxynaphthalene by ferric chloride in nitrobenzene has been put forward; the mechanism involves two charge transfer complexes and a radical cation as intermediate species. However, it has not proved possible to confirm this proposed mechanism through the observed kinetic data