ESTIMATION OF THE BEHAVIOR OF HYDROGEN IN NAPHTHALENE IN PYROLYSIS OFCOAL-TAR USING TRITIUM TRACER METHODS

The behaviour of hydrogen in naphthalene in the pyrolysis of coal tar was investigated using a tritium tracer technique to elucidate the pyr olysis mechanism of coal tar. The pyrolysis of coal tar containing tri tiated naphthalene was carried out using a batch reactor at 800-950 de grees C for 50 sec. The ratios of amounts of naphthalene in the tars p yrolysed at 800, 900, and 950 degrees C to that in the feed tar were 8 0.1, 73.4, and 42.5 wt%, respectively. However, the ratios of the radi oactivity of naphthalene in tars after pyrolysis to that in the feed t ar also decreased significantly with increasing temperature and it was only 12.9% for the reaction at 950 degrees C. The ratio of the recove red radioactivity of naphthalene to the initial radioactivity of napht halene in the feed tar was about one-third of that of the recovered am ount of naphthalene to the initial amount of naphthalene in the feed t ar at 950 degrees C. The results indicated that the hydrogen in naphth alene transferred to other compounds in the pyrolysis of coal tar. It is suggested that naphthalene could play an important part in the radi cal reaction mechanism in the pyrolysis of coal tar. (C) 1998 Elsevier Science Ltd. All rights reserved.