2,4-D

2,4-Dichlorophenoxyacetic acid

Names
IUPAC name (2,4-Dichlorophenoxy)acetic acid
Other names 2,4-D hedonal trinoxol
Identifiers
CAS Number	94-75-7 Y
3D model (Jmol)	Interactive image
ChEBI	CHEBI:28854 Y
ChEMBL	ChEMBL367623 Y
ChemSpider	1441 Y
ECHA InfoCard	100.002.147
KEGG	C03664 Y
PubChem	1486
UNII	2577AQ9262 N
InChI InChI=1S/C8H6Cl2O3/c9-5-1-2-7(6(10)3-5)13-4-8(11)12/h1-3H,4H2,(H,11,12) Y Key: OVSKIKFHRZPJSS-UHFFFAOYSA-N Y InChI=1/C8H6Cl2O3/c9-5-1-2-7(6(10)3-5)13-4-8(11)12/h1-3H,4H2,(H,11,12) Key: OVSKIKFHRZPJSS-UHFFFAOYAM
SMILES Clc1cc(Cl)ccc1OCC(=O)O
Properties
Chemical formula	C8H6Cl2O3
Molar mass	221.04 g/mol
Appearance	white to yellow powder
Melting point	140.5 °C (284.9 °F; 413.6 K)
Boiling point	160 °C (320 °F; 433 K) 0.4 mm Hg
Solubility in water	900 mg/L
Hazards
Flash point	nonflammable
Lethal dose or concentration (LD, LC):
LD50 (median dose)	500 mg/kg (oral, hamster) 100 mg/kg (oral, dog) 347 mg/kg (oral, mouse) 699 mg/kg (oral, rat)
US health exposure limits (NIOSH):
PEL (Permissible)	TWA 10 mg/m3
REL (Recommended)	TWA 10 mg/m3
IDLH (Immediate danger)	100 mg/m3
Related compounds
Related compounds	2,4,5-T, Dichlorprop
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

100 mg/kg (oral, dog)
347 mg/kg (oral, mouse)
699 mg/kg (oral, rat)

2,4-Dichlorophenoxyacetic acid (usually called 2,4-D) is an organic compound with the chemical formula C₈H₆Cl₂O₃. It is a systemic herbicide which selectively kills most broadleaf weeds by causing uncontrolled growth in them, but leaves most grasses such as cereals, lawn turf, and grassland relatively unaffected.

2,4-D is one of the oldest and most widely available herbicides in the world, having been commercially available since 1945, and is now produced by many chemical companies since the patent on it has long since expired. It can be found in numerous commercial lawn herbicide mixtures, and is widely used as a weedkiller on cereal crops, pastures, and orchards. Over 1,500 herbicide products contain 2,4-D as an active ingredient.

2,4-D is a possible carcinogen per WHO. The International Agency for Research on Cancer (IARC), the specialized cancer agency of the World Health Organization said 2,4-D was classified as "possibly carcinogenic to humans (Group 2B), based on inadequate evidence in humans and limited evidence in experimental animals". This puts 2,4-D in the same risk category as coffee and red meat but rates it as less likely to be carcinogenic than processed meat, which was placed in Group 1.

Some ester forms are highly toxic to fish and other aquatic life.

2,4-D was one of the ingredients in Agent Orange, a herbicide widely used during the Vietnam War. However, another ingredient in Agent Orange, 2,4,5-T (since banned in the United States), and its contaminant dioxin, were the cause of the adverse health effects associated with Agent Orange.