THERMAL-DISSOCIATION OF TETRALIN BETWEEN 300-DEGREES-C AND 450-DEGREES-C

Most studies of the hydrogenation of coal in hydrogen-donor solvents involve the reaction of hydrogen with coal slurried in tetralin, with or without catalysts. Reaction schemes proposed usually ignore the possibility of the contribution of products of the thermal breakdown of tetralin itself. In the work presented below tetralin was heated for various periods at temperatures between 300 and 450 °C without hydrogen or coal, and the products were analysed by capillary chromatography. The main products formed were naphthalene and the tetralin isomer 1-methyl indan. Tetralin did not disproportionate to naphthalene and decalin, although this has been suggested in the literature as a mechanism for the formation of the naphthalene usually observed. Naphthalene was produced, at temperatures as low as 350 to 400 °C, by dehydrogenation of the saturated ring. This ring also rearranged to give 1-methyl indan, and at higher temperatures broke open to yield alkyl benzenes. This cracking of the saturated ring was found to enhance the naphthalene formation. © 1979.