REACTIVITY OF THE SOOT PRODUCED DURING PYROLYSIS OF HEXACHLOROBENZENE- INFLUENCE OF THE PRESENCE OF CHLORINE

High temperature pyrolysis (1050-1200 degrees C) of hexachlorobenzene under inert atmosphere leads to the formation of soot. The objective o f this work is to characterize and study the soot and its reactivity w ith oxygen. SEM and TEM analysis show individual spherules with a mean diameter of 0.14 mu m, and small aggregates and agglomerates are also observed. The bulk apparent density of 435 kg m(-3) and the specific area of 20 m(2) g(-1) suggest a material with no meso or macroporosity . Ultimate analysis shows that the soot contains mainly carbon and chl orine in a proportion of 80/10 by weight. ESCA data indicate the prese nce of chlorine bound to aromatic (Csp(2)-Cl) and aliphatic (Csp(3)-Cl ) carbons. Correlation between the temperature of preparation and the percentage of chlorine in the soot has been put in evidence: the highe r the temperature of preparation, the lower is the amount of chlorine in the soot. The reactivity of soot prepared at 1100 degrees C has bee n compared to that of methane soot and the soot of a methane/hexachlor obenzene mixture obtained in the same experimental conditions. Compari son of the reactivity with that of carbon black has also been done. So ot structure and its chlorine content seem to exhibit a marked influen ce on the reactivity with oxygen (chlorine inhibiting the reactivity o f soot).