Investigation of the combustion of iron pentacarbonyl and the formation of key intermediates in iron oxide synthesis flames.

• Investigation of iron pentacarbonyl-doped low-pressure H 2 /O 2 /Ar flames by MBMS. • Evaluation of a chemical reaction mechanism for iron pentacarbonyl. • Ion chemistry of iron pentacarbonyl. • Iron hydroxides and iron oxides. • Ion sampling from flames. The information of the gas phase kinetics are relevant for the development of detailed reaction mechanisms as well as for process design and control in flame synthesis. In this study, the decomposition of iron pentacarbonyl and the reaction pathways towards iron oxide clusters and particles in laminar H 2 /O 2 /Ar low-pressure synthesis flames are investigated. Gas-phase species are analyzed by photoionization and electron ionization mass spectrometry. The extraction of a representative sample from the particle-laden flow of a synthesis flame by an intrusive sampling technique for the analysis is challenging, because iron-intermediate species can condense easily. Cations can be extracted from the flame with a high efficient ion sampling technique that results in high sensitivity. Iron-containing cations provide evidence of the presence of key intermediates, e.g., Fe(OH) 2 , Fe(OH) 3 , Fe 2 O 3 , and larger Fe-O-clusters which are the dominant intermediates with respect to particle formation and need to be considered in future gas-phase reaction mechanisms. [ABSTRACT FROM AUTHOR]