Model reactions and natural occurrence of furans from hypersaline environments

Abstract

Abstract. Volatile organic compounds like furan and its derivatives are important for atmospheric properties and reactions. In this paper the known abiotic formation of furan from catechol under Fenton-like conditions with Fe3+ sulphate was revised by the use of a bispidine Fe2+ complex as a~model compound for iron with well-known characteristics. While total yields were comparable to those with the Fe3+ salt, the turnover numbers of the active iron species increased. Additionally, the role of iron and pH will be discussed during furan formation from model compounds and in natural sediment and water samples collected from the Dead Sea and several salt lakes in Western Australia. Various alkylated furans and even traces of halogenated furans (3-chlorofuran and 3-bromofuran) were found in these samples. Furthermore, the emission of furans is compared to the abundance of several possible precursors such as isoprene and aromatic hydrocarbons as well as to the related thiophenes. It is assumed that the emissions of volatile organic compounds such as furans contribute to the formation of ultra fine particles in the vicinity of salt lakes and are therefore important for the local climate.