Mechanism of the Gas Phase, Thermal Decomposition of Ozone

The pyrolysis of ozone has been reinvestigated experimentally, and it is now shown that most of the known data are quantitatively explained on the basis of the simple mechanism, M+O3[open phi] lim 21M+O2+OO+O3→ lim 32 O2, where M may be O2, O3, CO2, N2, He, etc. There is no evidence for a direct bimolecular reaction of ozone to produce O2 nor is there any evidence for important surface effects or energy chains. On the other hand, the results at very fast rates of decomposition indicate an acceleration which can be accounted for in terms of temperature gradients in the system. This region is usually very close to the thermal explosion limit.The values found for the rate constants are (for M equal to O3), k1=4.61±0.25×1012 exp(−24 000/RT) liter/mole−sec,k2=6.00±0.33×107exp(+600/RT) liter2/mole2−sec,k3=2.96±0.21×1010exp(−6000/RT) liter/mole−sec.The relative efficiencies of O2, N2, CO2, and He in activating O3 (compared to O3 itself) are, respectively, 0.44, 0.41, 1.06, and 0.34.As expected for energy transfe...

[1]  R. Hudson,et al.  Ionization Potential of the Free HO2 Radical and the H – O2 Bond Dissociation Energy , 1955 .

[2]  H. Johnston,et al.  Thermal Decomposition of Nitryl Chloride. I. Second-order Unimolecular Rate Study , 1954 .

[3]  D. Garvin.  The Oxidation of Carbon Monoxide in the Presence of Ozone1 , 1954 .

[4]  P. Harteck,et al.  The Decomposition of Ozone on the Surface of Glass Wool , 1953 .

[5]  K. E. Russell,et al.  Studies in energy transfer I. The combination of iodine atoms , 1953, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[6]  N. Davidson,et al.  Photoelectric Observation of the Rate of Recombination of Iodine Atoms , 1953 .

[7]  S. Benson,et al.  A Detailed Formulation of Kinetic Processes. II. The Role of Collision Processes , 1953 .

[8]  R. Norrish,et al.  The Recombination of Atoms I. Iodine Atoms in the Rare Gases , 1953, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[9]  S. Benson.  A Detailed Formulation of Kinetic Processes from the Point of View of the Activated Complex , 1952 .

[10]  M. Wilson,et al.  A Reinvestigation of the Vibration Spectrum of Ozone , 1948 .

[11]  G. Herzberg,et al.  Infrared and Raman spectra of polyatomic molecules , 1946 .

[12]  O. K. Rice.  On the Recombination of Iodine and Bromine Atoms , 1941 .

[13]  O. K. Rice.  The Role of Heat Conduction in Thermal Gaseous Explosions , 1940 .

[14]  L. J. Heidt.  The Photolysis of Dry Ozone at λλ 208, 254, 280 and 313 mμ. II. Reaction Kinetics , 1935 .

[15]  A. O. Allen,et al.  The Explosion of Azomethane1 , 1935 .

[16]  L. J. Heidt,et al.  The Photolysis of Dry Ozone at λ208, at λ254 and at λ280 mμ. I. Quantum Yields , 1934 .

[17]  H. Schumacher.  THE MECHANISM OF THE PHOTOCHEMICAL DECOMPOSITION OF OZONE , 1930 .

[18]  R. Tolman,et al.  THE THERMAL DECOMPOSITION OF OZONE. I. THE HOMOGENEITY, ORDER, SPECIFIC RATE AND DEPENDENCE OF RATE ON TOTAL PRESSURE , 1927 .

[19]  C. E. Thorp.  Bibliography of ozone technology , 1954 .

[20]  S. Benson.  Temperature Gradients in Reacting Systems , 1954 .

[21]  G. Herzberg,et al.  Spectra of diatomic molecules , 1950 .