Formation of azulene and naphthalene from piperylene

Piperylene mixed with air is converted into a mixture of aromatics containing azulene and naphthalene on contact with bisnuith oxide at -600 °C. The yield of azulene and naphthalene is 6–8 %, The reaction is accompanied by burning of some of the piperylene and by the reduction of Bi₂O₃ to Bi metal. When the initial mixture is diluted with steam no reduction occurs. The reaction is believed to involve elimination of the allylic hydrogen, formation of dienyl radicals, their dimerization, and subsequent aromatization.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1556–1558, June, 1996.