Abstract
Aqueous solution phase photochemistry of the herbicide bromoxynil (3,5-dibromo-4-hydroxybenzonitrile) (1) in the presence of various concentrations of sodium chloride was extensively investigated with ultraviolet radiation near 313 nm. In the presence of 0.5 to 25.0x10−3 M NaCl, the quantam yields for the phototransformation of the herbicide bromoxynil (1) amounted to 0.045±0.005 to 0.017±0.007 vs. 0.052±0.004 in the absence of sodium chloride. These quantum yield data for the photolysis of1 followed the Stern-Volmer equation. The photolysis of the 7.8x10−6 M aqueous solution of the herbicide1 in the presence of sodium chloride (10.0x10−3 M) gave rise to the formation of 3-bromo-4-hydroxybenzonitrile (2), 3-bromo-5-chloro-4-hydroxybenzonitrile (3), 3-chloro-4-hydroxybenzonitrile (4), and 4-hydroxybenzonitrile (4A). The products3 and4 were formed via the photoincorporation of chloride ions into bromoxynil (1) and into the primary photoproduct2, respectively. In the case of this photoreaction of the chemical1, the percentages of maximum concentrations of the photoproducts3, 2, 4, and4A were obtained after 10.5, 20.0, 30.0, and 44.0-min exposures to UV light, respectively, the percentage disappearance of the starting material1 being 90% for 44-min photolysis. Photoproducts 2,3, 4, and4A were identified with the aid of GC-MS. The formation of 4-hydroxybenzonitrile (4A) decreased with the rise in concentration of NaCl. When a mixture of aqueous solutions of 3.0 mL bromoxynil (2.0x10−4M) plus 0.5 mL NaCl (0.5 M) was exposed to UV light for up to 3 hr, the photoproduct4A could not be observed; however, other products, namely, phenols2–4 were produced.
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References
Barltrop JA, Coyle JD (1975) Excited States in Organic Chemistry, John Wiley, NY pp 1–375
Brown DF, McDonough LM, McCool DK, Papendick RJ (1984) High-performance liquid Chromatographic determination of bromoxynil octanoate and metribuzin in runoff water from wheat fields. J Agric Food Chem 32:195–200.
Calvert JG, Pitts JN (1966) Photochemistry, John Wiley, NY, pp 1–830
Choudhry GG (1984) Humic Substances: Structural, Photophysical, Photochemical and Free Radical Aspects and Interactions with Environmental Chemicals, Gordon and Breach, NY, pp 1–185
Choudhry GG, Webster GRB (1985a) Protocol guidelines for the investigations of photochemical fate of pesticides in water, air, and soils. Residue Reviews 96:79–136
—, — (1985b) Environmental photochemistry of PCDDs. Part 1. Kinetics and quantum yields of the photodegradation of 1,2,3,4,7-penta- and 1,2,3,4,7,8-hexachlorodibenzo-p-dioxin in aqueous acetonitrile. Chemosphere 14:9–26
—, — (1985c) Photochemistry of halogenated benzene derivatives. V. Photolytic reductive dechlorination and isomerization of tetrachlorobenzenes in acetonitrile-water mixtures. Toxicol Environ Chem 9:291–308
Choudhry GG, Graham NJ, Webster GRB (1987) Photochemistry of halogenated benzene derivatives. VII. Photoformation of 2-methyl-4,5,6,7-tetrachlorobenzoxazole from pentachlorophenol in water-acetonitrile. Can J Chem 65:2223–2233
Choudhry GG, Roof AAM, Hutzinger O (1982) Photochemistry of halogenated benzene derivatives. II. Photoreactions ofα-substituted p-chlorotoluenes. J Chem Soc Perkin Trans I:2957–2961
Choudhry GG, Webster GRB, Hutzinger O (1986) Environmentally significant photochemistry of chlorinated benzenes and their derivatives in aquatic systems. Toxicol Environ Chem 13:27–83
Dulin D, Mill T (1982) Development and evaluation of sunlight actinometers. Environ Sci Technol 18:815–820
Kochany J, Lipczynska-Kochany E (1987) Analytical problems in determination of photoproducts of hydroxamic acids. Sci Total Environ 67:69–74
Kochany, J, Choudhry GG, Webster GRB (1989a) Photochemistry of halogenated benzene derivatives. IX. Environmental aquatic phototransformation of bromoxynil (3,5-dibromo-4-hydroxy-benzonitrile) herbicide. Pesticide Sci: (Submitted for publication)
-, -, - (1989b) Soil organic matter chemistry. Part 2. Effects of fulvic acids on the environmental photodecomposition of bromoxynil (3,5-dibromo-4-hydroxybenzonitrile) herbicide in water. Photochem Photobiol: (Submitted for publication)
Manitoba Agriculture (1988) Guide to Chemical Weed Control, Winnipeg, Government of Manitoba, Canada, pp 1–139
McLafferty FW (1973) Interpretation of Mass Spectra, WA Benjamin, NY, pp 16–30
Marcheterre L, Choudhry GG, Webster GRB (1988) Environmental photochemistry of herbicides. Rev Environ Contam Toxicol 103:61–126
Worthing ChR, Walker SB, (eds) (1987) The Pesticide Manual. A Word Compendium, VIII Edition, Lavenham Press Ltd, Lavenham, pp 100–101
Zafiriou OC, Joussot-Dubien J, Zepp RG, Zika RG, (1984) Photochemistry of natural waters: Many compounds and environments are affected by sunlight-induced photochemistry. Environ Sci Technol 18:358A-371A
Zepp RG (1982) Experimental approaches to environmental photochemistry, in: Hutzinger O (ed) The Handbook of Environmental Chemistry, Springer-Verlag, Berlin, pp 19–44
Zika RG, Cooper WJ, Eds. (1987) Photochemistry of Environmental Aquatic Systems, ACS Sympos Ser, Vol. 327. American Chemical Society, Washington, DC, pp 1–228
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For Part IX, see Kochanyet al. (1989a).
Visiting professor on sabbatical leave from Institute for Environmental Protection, Warsaw, Poland.
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Kochany, J., Choudhry, G.G. & Webster, G.R.B. Photochemistry of halogenated benzene derivatives. X. Effects of sodium chloride on the aquatic photodegradation of bromoxynil (3,5-Dibromo-4-hydroxybenzonitrile) herbicide. Arch. Environ. Contam. Toxicol. 19, 325–331 (1990). https://doi.org/10.1007/BF01054973
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DOI: https://doi.org/10.1007/BF01054973