Degradation of an ether-alcohol (3-ethoxypropan-1-ol) by photo-Fenton-generated aEuro¢OH radicals: products analysis and formation pathways; relevance to atmospheric water-phase chemistry

We have chosen 3-ethoxypropan-1-ol (EtOPrOH) as a typical short-carbon-chain ether-alcohol used as industrial solvent and have analyzed the degradation products resulting from its attack by (OH)-O-aEuro cent radicals generated by the photo-Fenton reaction. The laboratory conditions were representative of those found in tropospheric water droplets. Twelve products have been identified by use of GC-MS analysis, either directly or after extraction by SPME fibers, and by HPLC-UV analysis with a special column for carboxylic acids and after reaction of carbonyl groups with 2,4-dinitrophenylhydrazine. These products contain one to three carbon atoms (instead of five in EtOPrOH), among which one or two are oxidized. According to the reaction pathways proposed, seven products-including methanal-can result from attack by one (OH)-O-aEuro cent only, three products imply attack by a second (OH)-O-aEuro cent, as expected from their higher oxidation number, and it is suggested that reaction between two organic radicals is needed for formation of only two products. The relevance of this investigation to the fate of EtOPrOH and similar ether-alcohols in the troposphere is briefly discussed.