Technological limitations in the isolation of individual components of hard-coal tar by fractional distillation

Hard-coal tar is the source of a valuable raw material for the chemical industry. It contains considerable amounts of naphthalene and its homologs, indole, acenaphthene, dibenzofuran and fluorene. Of the above-mentioned substances, naphthalene is isolated on the industrial scale, and the resources of the other components are scarcely utilized. The difficulties in the creation of a rational technology for isolating the individual components are determined to some degree by the inadequacy of the study of the physicochemical laws of the separation of a hard-coal tar as a polyazeotropic-polyeutectic mixture. In the reported study, the technological limitations arising in the isolation from hard-coal tar by fractional distillation of naphthalene and its homologs, biphenyl, acenaphthene, dibenzofuran and fluorene have been investigated by the method of thermodynamic-topological analysis. 5 refs.