Reactivity of Coke. I. Absolute Reaction Rates of the Carbon Dioxide-Carbon Reaction

Abstract

Abstract The absolute reaction rates of carbon dioxide with eight carbons have been obtained from the surface area measurement by the B.E.T. method using ammonia adsorption at 0°C and the reaction rate measurement. The activation energies ranged from 91 Kcal/mol of oil coke and coke III to 99 Kcal/mol of coke I and pitch coke. The reaction mechanism that the reaction of the formation of surface oxide is rapid and always in equilibrium and the concentration of the surface oxide is negligibly small compared with total active centers and the rate-determining step is the desorption of surface oxide can be interpreted by the theory of absolute reaction rates. It may be concluded that the difference of the activation energies will be due to catalytic effects of some impurities in carbons, and that the difference of the absolute reaction rates due only to the difference of the crystallographic structure of pure carbons without the catalytic effects of impurities will be small.