Degradation intermediates and reaction pathway of pyraclostrobin with TiO2 photocatalysis

  1. Lagunas-Allué, L. 12
  2. Martínez-Soria, M.-T. 1
  3. Sanz-Asensio, J. 1
  4. Salvador, A. 2
  5. Ferronato, C. 2
  6. Chovelon, J.M. 2
  1. 1 Universidad de La Rioja
    info

    Universidad de La Rioja

    Logroño, España

    ROR https://ror.org/0553yr311

  2. 2 Claude Bernard University Lyon 1
    info

    Claude Bernard University Lyon 1

    Villeurbanne, Francia

    ROR https://ror.org/029brtt94

Revista:
Applied Catalysis B: Environmental

ISSN: 0926-3373

Año de publicación: 2012

Volumen: 115-116

Número: 1

Páginas: 285-293

Tipo: Artículo

DOI: 10.1016/J.APCATB.2011.12.015 SCOPUS: 2-s2.0-84856013045 WoS: WOS:000302429600033 GOOGLE SCHOLAR

Otras publicaciones en: Applied Catalysis B: Environmental

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Resumen

The present study deals with the photocatalytic degradation of the strobilurin pyraclostrobin in the presence of titanium dioxide (TiO 2) as a photocatalyst and UV light irradiation. The obtained results show a complete degradation of pyraclostrobin at pH 6.2, temperature at 20±1°C and 0.5gL -1 of catalyst after 60min irradiation. Photodegradation of pyraclostrobin exhibited pseudo-first-order reaction kinetics. The rate of photodecomposition of pyraclostrobin was measured using high performance liquid chromatography-diode array detector (HPLC-DAD). The effect of solution pH in the 2-10 range was investigated as well as the reaction intermediates formed during degradation. To obtain a better understanding of the mechanistic details of this TiO 2-assisted photodegradation of pyraclostrobin with UV-irradiation, the intermediates of the processes were concentrated, separated and identified by the solid-phase extraction (SPE) and liquid chromatography/mass spectrometry (LC-MS/MS) technique. The probable photodegradation pathways were proposed and discussed. The main steps involved: hydroxylation of the aromatic rings (chloro-phenyl, phenyl and pyrazol) followed by the loss of the N-methoxy group, substitution of chloride atom by a hydroxyl group, rupture of the pyrazol and phenyl bond and the scission of the oxygen and pyrazol bond. © 2011 Elsevier B.V..