Triclopyr

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Triclopyr^[1]

IUPAC name	[(3,5,6-Trichloro-2-pyridinyl)oxy]acetic acid
Identifiers
CAS number	[55335-06-3]
SMILES	ClC1=C(OCC(O)=O)N=C(Cl)C(Cl)=C1
Properties
Molecular formula	C₇H₄C_l3NO₃
Molar mass	256.46
Appearance	Fluffy solid
Melting point	148-150 °C
Solubility in water	440 mg/L
Solubility in acetone	989 g/kg
Acidity (pK_a)	2.68
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Triclopyr is a systemic, foliar herbicide in the pyridine group. It is used to control broadleaf weeds while leaving grasses and conifers unaffected.

Triclopyr is unusually effective on woody plants and is used for brush control in rights of way and defoliation of wooded areas. It is sold under the trade name Garlon for these purposes.

Also handy for broadleaf weeds, particularly Creeping Charlie, upon which it is uncommonly effective. It is sold under the trade names Turflon, and Weed-B-Gone (purple label) for these purposes. Also the second major ingredient in Confront, which also contains clopyralid, and was withdrawn from most uses due to concerns about compost contamination from the clopyralid.

Triclopyr is formulated both as an ester and as an amine salt. The usual tradeoffs regarding effectiveness, drift, and toxicity to humans apply to these two formulations.

[edit] Environmental Issues

Triclopyr breaks down in soil with a half-life of between 30 and 90 days. One of the byproducts of breakdown (trichloro-pyridinol) remains in the soil for up to a year. Triclopyr degrades rapidly in water. It remains active in decaying vegetation for about 3 months.

The compound is slightly toxic to ducks (LD₅₀ = 1698 ppm) and quail (LD₅₀ = 3000 ppm).^[2] It has been found non-toxic to bees and fish.