Investigation of the photochemistry and quantum yields of triazines using polychromatic irradiation and UV-spectroscopy as analytical tool
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In: International Journal of Environmental Analytical Chemistry, Vol. 65, No. 1-4, 01.12.1996, p. 313-329.
Research output: Journal contributions › Journal articles › Research
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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 -