The slow oxidation of carbon monoxide

Outside the explosion peninsula, particularly in the region above the second limit, the oxidation of CO can take place at a speed convenient for normal kinetic measurements. As with the explosive combustion, the kinetics are very sensitive to the surface and to the purity of the reacting gases. 

Verdurmen [375] showed that the rate of production of CO2 in quartz vessels at these temperatures was proportional to the surface area. 

The reaction is promoted by small additions of hydrogenous materials, the kinetics being radically altered with the rate of oxidation. Near the tip of the explosion peninsula [374] the rate is proportional to [CO] [H2]/ 

The results of Hadman et al. [374], except when iodine was present, are somewhat contrary to a more detailed investigation of Tsvetkova et al. [376], who found the reaction to be first order with respect to H2O (for small additions of water) and also to increase with both [CO] and [O2], though in a complex manner. Tipper and Williams [372] also found that oxygen may have had a retarding effect on the rate of oxidation of wet 

but it appeared that the oxygen could have changed the nature of the vessel surface, which was coated with boric acid. They finally concluded that the addition of CO, O2 or N2 had little effect on the initial oxidation rate. On the other hand, Hoare and Walsh [357] found an increase in the oxidation rate when the concentration of either the carbon monoxide or oxygen was raised. The contrasting results on the effect of oxygen are shown in Fig. 63 and 64. 

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