The kinetics of the reaction between oxygen and gaseous methyl ethyl ketone (butanone) have been investigated in the range 250 to 450° C. The anomalous temperature coefficient of the rate offers a good example of the transition from a low-temperature mode of oxidation to a high-temperature mode. Similar behaviour has been observed with hydrocarbons and is ascribable to the diminishing part played at higher temperatures by the peroxides, which at low temperatures play a key role in generating branching chains. In the low-temperature range the rate of oxidation varies steeply with the initial pressure of butanone and is a very unusual function of the oxygen pressure, passing through a sharp maximum at certain pressures above which the rate falls and then tends to become constant. The maximum tends to disappear as the temperature is raised. Increase of the surface / volume ratio causes a diminution in rate, while addition of inert gases has no appreciable influence. The various complex relationships are well accounted for in their general form by a modification of the theory previously applied to pentane and hexane. This theory postulates a series of reaction steps of maximum simplicity, permitting a slow branching of chains by fission of peroxides. It leads to a rate expression which according to circumstances may become infinite at certain critical concentrations or remain finite throughout. The critical limits may be related to explosions or cool flames. In the application to butanone oxidation the peculiar form of the dependence of rate on oxygen pressure may be accounted for and a general account given of the observed cool-flame limits. The agreement of the theory with a number of rather unusual facts is considered to be of greater significance than its lack of quantitative accuracy which is ascribed to the approximate nature of its basis.
Understanding the Promotional Effect of Mn2O3 on Micro-/Mesoporous Hybrid Silica Nanocubic-Supported Pt Catalysts for the Low-Temperature Destruction of Methyl Ethyl Ketone: An Experimental and Theoretical Study
