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| Names | |
|---|---|
| Preferred IUPAC name
3,5-dichloro-4-hydroxybenzonitrile | |
| Identifiers | |
3D model (JSmol)
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| ECHA InfoCard | 100.015.976 |
| EC Number |
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PubChem CID
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| UNII | |
CompTox Dashboard (EPA)
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| Properties | |
| C7H3Cl2NO | |
| Molar mass | 188.01 g·mol−1 |
| Appearance | Off-white solid1 |
| Melting point | 140 °C (284 °F; 413 K)3 |
| Slightly soluble2 | |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards
|
Toxic, harmful to aquatic life, irritant |
| GHS labelling:1 | |
| |
| Danger | |
| H301, H311, H315, H319, H331, H335 | |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose)
|
200 mg/kg (oral, rat)4 |
LC50 (median concentration)
|
21.4-27.5mg/L (96h, Pimephales promelas)1 |
| Related compounds | |
Related compounds
|
Ioxynil, Bromoxynil, Bromoxynil octanoate |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Chloroxynil is a postemergent5 benzonitrile herbicide, used to control broad leaved weeds on cereal crops. It was manufactured by Rhone-Poulenc and May & Baker, and is now considered obsolete, though its usage may continue.4
Chloroxynil was developed as a variant of bromoxynil, which is identical except for bromines replacing chloroxynil's chlorines. A 1972 study found chloroxynil less injurious to alfalfa and red clover, but also less potent at controlling broadleaf weeds.6
Chloroxynil's MoA inhibits electron transfer in the photosystem II receptor.7 Its HRAC group is Group C, (Australia) C3 (global) or 6 (numeric).4
Genetic engineering
Chloroxynil can greatly improve the speed and efficiency of agrobacterium-mediated transformation of plants. Compared to the control, acetosyringone was 6 times faster, and chloroxynil was 60 times faster. Chloroxynil's related herbicides were also tested: bromoxynil was 18 times faster than control but caused plant damage, and ioxynil showed no significant improvement.8
Soil behaviour
In soil, chloroxynil lasts about a month in aerobic soil (soil with sufficient oxygen to support microbial activity), or about two weeks in anaerobic soil.5 Sunlight can photochemically degrade it, by splitting off the chlorine atoms.9
Application
Chloroxynil was used on wheat, barley, oats, lucerne, sorghum and fax, to control pigweed, mayweed, knotweed, shepherd's purse, goosefoot and stinkweed.4
References
References
- "Chloroxynil | CAS 1891-95-8 | LGC Standards". www.lgcstandards.com. Retrieved 8 April 2025.
- "Chloroxynil, 97+%, Thermo Scientific Chemicals". www.thermofisher.com.
- "AstaTech Inc. Catalog Product Search Result". astatechinc.com.
- Hertfordshire, University of. "Chloroxynil (Pesticide Properties Database)". sitem.herts.ac.uk.
- Nolte, J.; Heimlich, F.; Graß, B.; Zullei-Seibert, N.; Preuss, G. (1995). "Studies on the behaviour of dihalogenated hydroxybenzonitriles in water". Fresenius' Journal of Analytical Chemistry. 351 (1): 88–91. doi:10.1007/BF00324296.
- Peters, Elroy J.; Lowance, S. A. (1972). "Bromoxynil, Chloroxynil, and 2,4-DB for Establishing Alfalfa and Medium Red Clover". Weed Science. 20 (2): 140–142. Bibcode:1972WeedS..20..140P. doi:10.1017/S0043174500035190. ISSN 0043-1745. JSTOR 4042177.
- "Pestanal Chloroxynil Standard". sigmaaldrich.com. Retrieved 8 April 2025.
- Kimura, Mitsuhiro; Cutler, Sean; Isobe, Sachiko (15 July 2015). "A Novel Phenolic Compound, Chloroxynil, Improves Agrobacterium-Mediated Transient Transformation in Lotus japonicus". PLOS ONE. 10 (7) e0131626. Bibcode:2015PLoSO..1031626K. doi:10.1371/journal.pone.0131626. PMC 4503419.
- Malouki, Moulay A.; Zertal, Abdennour; Lavédrine, Bernadette; Sehili, Tahar; Boule, Pierre (November 2004). "Phototransformation of 3,5-dihalogeno-4-hydroxybenzonitriles (ioxynil and chloroxynil) in aqueous solution". Journal of Photochemistry and Photobiology A: Chemistry. 168 (1–2): 15–22. Bibcode:2004JPPA..168...15M. doi:10.1016/j.jphotochem.2004.05.007.