Experimental study of the heterogeneous reactivity between atomic chlorine and palmitic acid films
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The present study focuses on the heterogeneous reaction between gaseous atomic chlorine and solid palmitic acid films, used as a proxy of the fatty acids detected in atmospheric airborne particles. This reaction is investigated in a coated wall flow tube reactor coupled to a molecular beam mass spectrometer. The reactive surfaces were prepared by coating the inner surface of the reactor. The initial Cl˙ and Cl2 uptake coefficient measured for these heterogeneous reactions is found to be fast: γo Cl = 0.07. The rapid formation of hydrogen chloride corresponding with the disappearance of atomic chlorine is highlighted. Furthermore, the formation of new chlorinated species on the solid substrate has been detected by TOF SIMS analysis leading to an ageing process of the surface. A heterogeneous recombination of Cl atoms to Cl2 molecules was observed for aged surfaces.
KeywordsMultiphase chemistry Atomic chlorine Palmitic acid films Uptake coefficient
This work is a part of the IRENI program, financially supported by the Nord Pas-de-Calais Regional Council and by the European Regional Development Fund. Funding was also provided by a Marie Curie fellowship. The authors thank N. Nuns for TOF SIMS analyses.
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