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Despite their atmospheric abundance, heterogeneous and multiphase reactions of carbonyl compounds are poorly understood. In this study, we investigate the surface adsorption and surface chemistry of methyl ethyl ketone (MEK), the second most abundant ketone in the atmosphere, with several mineral oxide surfaces including SiO 2 , α-Fe 2 O 3 and TiO 2 . In particular, the chemistry of MEK with these common components of mineral dust, under both dry and high relative humidity (RH%) conditions, has been investigated. Furthermore, reactions of adsorbed MEK with gas-phase NO 2 were also examined. We show that MEK molecularly and reversibly adsorbs on SiO 2 whereas irreversible adsorption occurs on both α-Fe 2 O 3 and TiO 2 surfaces, followed by the formation of higher molar mass species resulting from dimerization and oligomerization reactions. Isotope labeling experiments confirmed the incorporation of H atoms from surface hydroxyl groups and strongly adsorbed water into these oligomer products. Most interesting is that at 80% RH, oligomer formation on α-Fe 2 O 3 shifts toward a higher relative abundance of MEK tetramer relative to the dimer while on TiO 2 there was no change in product distribution. In the presence of gas-phase NO 2 , MEK undergoes degradation to formaldehyde and acetaldehyde, followed by the formation of aldol condensation products of these aldehydes on the α-Fe 2 O 3 surface. Overall, this study provides mechanistic insights on mineralogy-specific heterogeneous chemistry of a prevalent and atmospherically abundant ketone.