Department of Chemistry, Faculty of Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka 259-1293, Japan.
Chemosphere. 2011 Feb;82(8):1129-34. doi: 10.1016/j.chemosphere.2010.11.038. Epub 2010 Dec 8.
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.
杂多酸光催化剂 H4SiW12O40引发氢全氟羧酸[H-PFCAs；HC(n)F(2)(n)COOH(n=4 和 6)]在水中的分解，并将结果与相应的全氟羧酸（PFCAs；C(n)F(2)(n)(+1)COOH）的结果进行比较。这是关于 H-PFCAs 光化学分解的首次报道，H-PFCAs 正在作为对环境持久性和生物累积性 PFCAs 的替代品开发。在没有 H4SiW12O40的情况下，用紫外线-可见光（>290nm）照射不会使 H-PFCAs 分解。相比之下，在 H4SiW12O40存在下用紫外线-可见光照射 H-PFCAs 可以有效地将 H-PFCAs 分解为 F(-)和 CO2。分解反应表现出准一级动力学，分解速率常数比相应的 PFCAs 高 1.8-2.5 倍。反应机制可以解释为受激催化剂从 H-PFCAs 的ω-H 原子消除 H(+)，随后形成全氟二羧酸。
