Mechanistic Modeling of the Wall reactions in the pyrolysis of pentachloroethane

The thermal dehydrochlorination C2HCl5 [RIGHTWARDS ARROW] C2Cl4 + HCl has been studied in a static system between 565 and 645 K at pressures ranging from 5 to 21 torr. The course of the reaction was followed by measuring the pressure rise in the conditioned quartz reaction vessel and by analyzing the products by gas chromatography. The observed experimental results and data from the literature for flow systems can be explained quantitatively in terms of a radical reaction model involving heterogeneous chain initiation and termination steps. The rate constants have been deduced for reactions of Cl, Cl2, and C2HCl5 over reactor walls covered with a pyrolytic carbon film and for reactions of adsorbed Cl atoms.