Carbon, in the form of a
wood char activated by treatment with air and chlorine, has been
chlorinated directly at temperatures between 600� and 800� and at chlorine
pressures between 3.5 and 20 atm in a flow apparatus
to produce carbon tetrachloride as sole reaction product. The rate of formation
R of carbon tetrachloride can be expressed by the equation
R = ilpa
where il
is the rate constant for the chemisorption of
chlorine on carbon and pa is the partial pressure of chlorine. The
rate is also dependent on the nature of the carbon, high temperature carbons
being less reactive. The energy of activation for the process is 25 kcal mole-1.
When carbon tetrachloride
is decomposed in a carbon bed, tetrachloroethylene, hexachloroethane, chlorine, and carbon are formed as
products, the predominant species depending on the conditions. This indicated
that the overall reaction is not given by the simple equation
C + 2Cl2 + CCl4
(I)
and, on prolonged reaction
times, yields of carbon tetrachloride well below the amount expected at
equilibrium for this reaction confirm the finding.
pa denotes the
partial pressure of Cl2, pb that of CCl4, pc
that of C2C14, and pa that of CzCl6.The subscript numerals to i and j refer to the equation numbers in the text.
Effect of calcium dispersion and graphitization during high-temperature pyrolysis of beech wood char on the gasification rate with CO2
