To trace the behavior of naphthalene in the pyrolysis of coal tar, the pyrolysis of coal tar containing ^<14>C and ^3H labelled naphthalene was carried out at 800-950℃ for 40-50 sec. From the distribution of radioactivities, it was found that naphthalene has significant pyrolysis reactivity at 950℃, and the hydrogen of naphthalene transferred to other compounds. This tracer method using ^<14>C and ^3H labelled naphthalene is convenient for tracing the reactivity of coal tar and for elucidating the reaction mechanism of coal tar pyrolysis.
