TY - JOUR

T1 - Investigation of the photochemistry and quantum yields of triazines using polychromatic irradiation and UV-spectroscopy as analytical tool

AU - Palm, Wolf-Ulrich

AU - Zetzsch, Cornelius

PY - 1996/12/1

Y1 - 1996/12/1

N2 - Photochemical reactions of atrazine, propazine, simazine, terbuthylazine, ametryn and atraton were investigated in aqueous and buffered (pH = 7-9) solutions (containing a few percent of acetonitrile) using a polychromatic Xe light source at T = 22°C. For terbuthylazine the photochemistry is investigated in detail, including solvent-, temperature-and pH-dependence and products found. The role of polychromatic light sources used in investigations of the photochemistry of triazines is discussed. For the first time, quantum yield measurements were performed in the UV-band between 240-300 nm of the chlorotriazines and ametryn. Isosbestic points were found in the UV-spectra at different irradiation times, and UV-spectroscopy was used to obtain kinetic information. Quantum yields in aqueous solutions at T = 22°C for the chlorotriazines (Φ = 0.048-0.062) and for ametryn (Φ = 0.043) are comparable. The temperature dependence of the photoreaction of terbuthylazine leads to an activation energy of about 13 kJ mol-1. Quantum yields in acetonitrile and hexane for terbuthylazine are about half of the values found in aqueous solution. Atraton was not degradable under the conditions used, and the quantum yield could only be estimated to be Φ < 0.002.

AB - Photochemical reactions of atrazine, propazine, simazine, terbuthylazine, ametryn and atraton were investigated in aqueous and buffered (pH = 7-9) solutions (containing a few percent of acetonitrile) using a polychromatic Xe light source at T = 22°C. For terbuthylazine the photochemistry is investigated in detail, including solvent-, temperature-and pH-dependence and products found. The role of polychromatic light sources used in investigations of the photochemistry of triazines is discussed. For the first time, quantum yield measurements were performed in the UV-band between 240-300 nm of the chlorotriazines and ametryn. Isosbestic points were found in the UV-spectra at different irradiation times, and UV-spectroscopy was used to obtain kinetic information. Quantum yields in aqueous solutions at T = 22°C for the chlorotriazines (Φ = 0.048-0.062) and for ametryn (Φ = 0.043) are comparable. The temperature dependence of the photoreaction of terbuthylazine leads to an activation energy of about 13 kJ mol-1. Quantum yields in acetonitrile and hexane for terbuthylazine are about half of the values found in aqueous solution. Atraton was not degradable under the conditions used, and the quantum yield could only be estimated to be Φ < 0.002.

KW - HPLC

KW - polychromatic irradiation

KW - quantum yields

KW - temperature dependence

KW - Triazines

KW - UV-spectroscopy

KW - Chemistry

UR - http://www.scopus.com/inward/record.url?scp=0030499532&partnerID=8YFLogxK

U2 - 10.1080/03067319608045564

DO - 10.1080/03067319608045564

M3 - Journal articles

AN - SCOPUS:0030499532

VL - 65

SP - 313

EP - 329

JO - International Journal of Environmental Analytical Chemistry

JF - International Journal of Environmental Analytical Chemistry

SN - 0306-7319

IS - 1-4

T2 - 5th Symposium on Chemistry and Fate of Modern Pesticides

Y2 - 6 September 1995 through 8 September 1995

ER -