Title: Bromoxynil
CAS Registry Number: 1689-84-5
CAS Name: 3,5-Dibromo-4-hydroxybenzonitrile
Additional Names: 3,5-dibromo-4-hydroxyphenyl cyanide; 2,6-dibromo-4-cyanophenol; broxynil
Manufacturers' Codes: ENT-20852; MB-10064
Molecular Formula: C7H3Br2NO
Molecular Weight: 276.91
Percent Composition: C 30.36%, H 1.09%, Br 57.71%, N 5.06%, O 5.78%
Literature References: Selective contact herbicide. Prepn: K. Auwers, J. Reis, Ber. 29, 2359 (1896); E. Müller et al., Ber. 92, 2278 (1959); K. Carpenter et al., Weed Res. 4, 175 (1964); FR 1375311 (1964 to May & Baker), C.A. 62, 3982h (1965). Herbicidal activity: K. Carpenter, B. J. Heywood, Nature 200, 28 (1963). HPLC analysis: J. C. Van Damme, M. Galoux, J. Chromatogr. 190, 401 (1980). Persistence in soil: A. E. Smith, Pestic. Sci. 11, 341 (1980).
Properties: Colorless solid, mp 194-195°. pKa 4.06. Subl at 135° (0.15 mm Hg). Slightly volatile in steam. Soly in (g/l) at 25°: water 0.13; methanol 90; acetone 170; tetrahydrofuran 410. LD50 orally in mice: 111 mg/kg (Carpenter, 1964).
Melting point: mp 194-195°
pKa: pKa 4.06
Toxicity data: LD50 orally in mice: 111 mg/kg (Carpenter, 1964)
Derivative Type: Octanoate
CAS Registry Number: 1689-99-2
Manufacturers' Codes: MB-10731; NPH-1320; RP-16272
Trademarks: Brominal (Bayer CropSci.); Buctril (Bayer CropSci.)
Molecular Formula: C15H17Br2NO2
Molecular Weight: 403.11
Percent Composition: C 44.69%, H 4.25%, Br 39.64%, N 3.47%, O 7.94%
Properties: Waxy solid, mp 45-46°. Low volatility; subl at 90° (0.1 mm Hg). Insol in water.
Melting point: mp 45-46°
Use: Herbicide.
Bromperidol Brompheniramine Bromphenol Blue Bromthymol Blue Bromuconazole

CAS number 1689-84-5 YesY
PubChem 15531
ChemSpider 14775 YesY
KEGG C04178 YesY
ChEBI CHEBI:17192 YesY
Jmol-3D images Image 1
Molecular formula C7H3Br2NO
Molar mass 276.91 g mol−1
Density 2.243 g/mL
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Bromoxynil is a nitrile herbicide, trade names include Brominal, Bromotril, Bronate, Buctril, Certrol B, Litarol, M&B 10064, Merit, Pardner, Sabre, and Torch. It is used for post-emergent control of annual broadleaf weeds. It is especially effective in the control of weeds in cereal, corn, sorghum, onions, flax, mint, turf, and on non-cropland. It works by inhibiting photosynthesis. Lethal doses in mammals range between 60 and 600 milligrams ingested per kilogram of body weight, and teratogenic effects have been observed in rats and rabbits above 30 milligrams per kilogram. Chronic exposure for more than one year in humans caused symptoms of weight loss, fever, vomiting, headache, and urinary problems in one documented case.[1] In the United States it is distributed as a restricted use pesticide in toxicity class II (moderately toxic) and not available for homeowner use.

In the Great Plains region of Canada it is widely used on cereal grains. Average levels detected in drinking water were 1 nanogram per liter, but in one case as high as 384 nanograms per liter were detected. Levels of bromoxynil were consistently lower than of several other pesticides tested, and it was observed to undergo greater reduction in water treatment than the others.[2]

Bromoxynil decomposes readily in soil, with a half life of approximately two weeks. Persistence increases in soils with elevated clay or organic matter content, suggesting the compound has somewhat limited bioavailability to microorganisms in these environments. Under aerobic conditions in soils or pure cultures, products of bromoxynil degradation often retain the original bromine groups. The herbicide, and one of its common degradation products (3,5-dibromo-4-hydroxybenzoic acid) have been shown to undergo metabolic reductive dehalogenation by the microorganism, Desulfitobacterium chlororespirans.[3]