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

摘要

We have chosen 3-ethoxypropan-1-ol (EtOPrOH) as a typical shortcarbon-chain ether–alcohol used as industrial solvent and have analyzed the　degradation products resulting from its attack by OH 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 only, three products imply attack by a second OH, 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.