title: Photocatalytic mineralization of hydroperfluorocarboxylic acids with heteropolyacid H₄SiW₁₂O₄₀ in water.
abstract: The decomposition of hydroperfluorocarboxylic acids [H-PFCAs; HC(n)F(2)(n)COOH (n=4 and 6)] induced by heteropolyacid photocatalyst H(4)SiW(12)O(40) in water was investigated, and the results are compared with the results for the corresponding perfluorocarboxylic acids (PFCAs; C(n)F(2)(n)(+1)COOH). This is the first report on the photochemical decomposition of H-PFCAs, which are being developed as alternative surfactants to environmentally persistent and bioaccumulative PFCAs. H-PFCAs were not decomposed by irradiation with UV-Visible light (>290 nm) in the absence of H(4)SiW(12)O(40). In contrast, UV-Visible light irradiation of H-PFCAs in the presence of H(4)SiW(12)O(40) efficiently decomposed H-PFCAs to F(-) and CO(2). The decomposition reactions showed pseudo-first-order kinetics, and the decomposition rate constants were 1.8-2.5 times higher than those for the corresponding PFCAs. The reaction mechanism can be explained by elimination of H(+) from the ω-H atom of the H-PFCAs by the excited catalyst, followed by formation of perfluorodicarboxylic acids.
authors.affiliation: Department of Chemistry, Faculty of Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka 259-1293, Japan. h-hori@kanagawa-u.ac.jp
authors.forename: Hisao
authors.initials: H
authors.lastname: Hori
authors.forename: Kyoko
authors.initials: K
authors.lastname: Ishida
authors.forename: Naoko
authors.initials: N
authors.lastname: Inoue
authors.forename: Kazuhide
authors.initials: K
authors.lastname: Koike
authors.forename: Shuzo
authors.initials: S
authors.lastname: Kutsuna
mesh_terms: D002264:Carboxylic Acids / Q000737:chemistry*; D006845:Hydrocarbons, Fluorinated / Q000737:chemistry*; D007700:Kinetics; D055668:Photochemical Processes; D017655:Silicon Compounds / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry*; D014414:Tungsten / Q000737:chemistry*; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D002264:Carboxylic Acids; D006845:Hydrocarbons, Fluorinated; D017655:Silicon Compounds; D013501:Surface-Active Agents; D014874:Water Pollutants, Chemical; D014414:Tungsten