The effect of pyrolytic carbon coatings on a gas-phase free-radical reaction, the pyrolysis of 1,2-dichloroethane

Abstract

Carbon films have been prepared by the pyrolysis of allyl bromide and other organic compounds under known conditions of temperature and pressure. The free radical contents of such films have been measured by e.s.r. spectroscopy, and the weights of carbon deposited estimated by burning to carbon dioxide. A mean value of 1·4 × 10²⁰ spins/g. has been obtained for allyl bromide carbon prepared at 360°. No correlation has been observed between the spin contents of carbon coatings on Pyrex reaction vessels and the sbsequent rates of pyrolysis of 1,2-dichloroethane in those vessels. However, it has been shown that the rate of pyrolysis of this compound is dependent upon the nature of the surface coating. Faster rates are observed in vessels carbon-coated by allyl bromide and by 1,1,2-trichloroethane than those in which the coating is provided by the parent compound.