An experimental investigation of the mutually sensitised oxidation of nitric oxide and n-butane

Bromly, J.H., Barnes, F.J., Mandyczewsky, R., Edwards, T.J. and Haynes, B.S. (1992) An experimental investigation of the mutually sensitised oxidation of nitric oxide and n-butane. Symposium (International) on Combustion, 24 (1). pp. 899-907.

Abstract

The interaction between NO (0.01 to 200 ppm) and n-butane (50 to 600 ppm) in air has been investigated in a flow reactor at atmospheric pressure and temperatures from 330° C to 450° C (600 K to 720 K). Low concentrations of NO in n-butane/air systems promote the oxidation of the n-butane; conversely, low concentrations of n-butane in air promote the oxidation of NO to NO2. For given [NO]/[n-butane] ratio and reaction time, there is a critical sharply-defined 'crossover' temperature at which the system goes from being unreactive to reactive, with 100% conversion NO→NO2 occurring at T>Tcrossover. The crossover temperature increases, and becomes less sharply defined, with increasing [NO]/[n-butane] ratio. The conversion NO→NO2 is accompanied by the consumption of n-butane and the formation of CH3CHO, CO, HCHO, (CH3)2CO, various butenes, and propene. The extent of n-butane consumption depends in a complex manner on the experimental conditions especially on the relationship of the experiment temperature to the characteristic turnover temperature which marks the onset of the region of negative temperature coefficient (NTC) for n-butane/air reaction (≈380° C or 650 K). Trace quantities (as little as 0.02 ppm) of NO have a profound promoting effect on n-butane consumption in the vicinity of the turnover temperature by virtue of the ability of NO to convert unreactive HO2 radicals into reactive OH: HO2+NO→NO2+OH Other reactions of NO believed to be important in this system are RO2+NO→RO+NO2 and NO+OH+M→HONO+M. The mutual sensitisation of the oxidation of n-butane and NO has implications for emissions of NO2 from combustion appliances and for hydrocarbon ignition phenomena in the presence of NO, such as occurs in engines.

Item Type:	Journal Article
Murdoch Affiliation(s):	School of Mathematical and Physical Sciences
Publisher:	Combustion Institute
Copyright:	© 1992 Combustion Institute.
URI:	http://researchrepository.murdoch.edu.au/id/eprint/35783

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