Abstract: There is disclosed a method and apparatus for removing inhibiting substances produced in a dehydrogenation aromatization of poly cyclic compounds, the removal and consequent refinement of the reaction products occurring within the reaction system itself. To a dehydrogenation reaction apparatus comprising an evaporation section, a distillation, section, a reaction chamber including a catalyst bed section and a reflux condenser section, raw material is fed and then evaporated. After the vapor is passed through the catalyst zone section, it is liquefied at the reflux condenser section, and a portion or whole returned to the reaction chamber. The method is effective with poly cyclic compounds that cannot easily be handled by conventional methods. The reaction is highly efficient and proceeds with minimal catalyst deterioration.