Chloroxynil

{{Chembox

| ImageFile = Chloroxynil.svg

| ImageSize = 180px

| PIN = 3,5-dichloro-4-hydroxybenzonitrile

| OtherNames =

|Section1={{Chembox Identifiers

| CASNo = 1891-95-8

| ChEBI =

| ChEMBL =

| ChemSpiderID =

| EC_number = 217-572-4

| KEGG =

| PubChem = 74685

| UNII = GI6X21WSVN

| StdInChI= 1S/C7H3Cl2NO/c8-5-1-4(3-10)2-6(9)7(5)11/h1-2,11H

| StdInChIKey = YRSSHOVRSMQULE-UHFFFAOYSA-N

| SMILES = C1=C(C=C(C(=C1Cl)O)Cl)C#N

}}

|Section2={{Chembox Properties

| C=7|H=3|Cl=2|N=1|O=1

| Appearance = Off-white solid

| Density =

| MeltingPtC = 140

| MeltingPt_ref ={{cite web |title=AstaTech Inc. Catalog Product Search Result |url=https://astatechinc.com/CPSResult.php?CRNO=41761 |website=astatechinc.com}}

| BoilingPtC =

| BoilingPt_notes =

| BoilingPt_ref =

| Solubility = Slightly soluble{{cite web |title=Chloroxynil, 97+%, Thermo Scientific Chemicals |url=https://www.thermofisher.com/order/catalog/product/H50432.03 |website=www.thermofisher.com |language=en}}

| VaporPressure =

}}

|Section3={{Chembox Hazards

| MainHazards = Toxic, harmful to aquatic life, irritant

| GHS_ref =

| GHSPictograms = {{GHS06}}

| GHSSignalWord = Danger

| HPhrases = {{HPhrases|301|311|315|319|331|335}}

| PPhrases =

| FlashPt =

| LD50 = 200 mg/kg (oral, rat){{cite web |last1=Hertfordshire |first1=University of |title=Chloroxynil (Pesticide Properties Database) |url=http://sitem.herts.ac.uk/aeru/ppdb/en/Reports/2734.htm |website=sitem.herts.ac.uk}}

|LC50 = 21.4-27.5mg/L (96h, Pimephales promelas){{cite web |title=Chloroxynil {{!}} CAS 1891-95-8 {{!}} LGC Standards |url=https://www.lgcstandards.com/GB/en/Chloroxynil/p/DRE-C11550000 |website=www.lgcstandards.com |access-date=8 April 2025}}

| AutoignitionPt =

}}

}}

Chloroxynil is a postemergent 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.

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.{{cite journal |last1=Peters |first1=Elroy J. |last2=Lowance |first2=S. A. |title=Bromoxynil, Chloroxynil, and 2,4-DB for Establishing Alfalfa and Medium Red Clover |journal=Weed Science |date=1972 |volume=20 |issue=2 |pages=140–142 |doi=10.1017/S0043174500035190 |jstor=4042177 |bibcode=1972WeedS..20..140P |url=https://www.jstor.org/stable/4042177 |issn=0043-1745}}

Chloroxynil's MoA inhibits electron transfer in the photosystem II receptor.{{cite web |title=Pestanal Chloroxynil Standard |url=https://www.sigmaaldrich.com/AU/en/product/sial/33363?utm_source=pubchem&utm_campaign=pubchem_2017&utm_medium=referral |website=sigmaaldrich.com |access-date=8 April 2025}} Its HRAC group is Group C, (Australia) C3 (global) or 6 (numeric).