2,4-Dichlorophenoxyacetic Acid

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2,4-dichlorophenoxyacetic acid

[¦tü ¦fȯr dī¦klȯr·ō·fə¦näk·sē·ə′sēd·ik ′as·əd]
(organic chemistry)
Cl2C6H3OCH2COOH Yellow crystals, melting at 142°C; used as a herbicide and pesticide. Abbreviated 2,4-D.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

2,4-Dichlorophenoxyacetic Acid


(also called 2,4-D), C12C6H3OCH2COOH, a herbicide for combating dicotyledonous weeds in sowings of grain crops and in meadows. In pure form it exists as white odorless crystals; melting point, 140.5° C. Its solubility in water is 560 mg per liter at 20° C. The industrial preparation has an unpleasant phenolic odor caused by an admixture of 2,4-dichlorophenol. In industry, 2,4-D is made by the reaction of salts of monochloroacetic acid with sodium 2,4-dichlorophenate and by chlorination of phenoxyacetic acid. It is the most extensively produced and utilized herbicide. It is used in the form of water-soluble salts with acyclic amines (dimethylamine, diethylamine, ethanolamines, and so on) and in the form of a sodium salt, esters with various alcohols (isopropanol, butanol, octanol, and others), and amides (for example, the o-chloroanilide).

At the consumption levels of 0.5-2.0 kg per hectare (kg/ha), almost all dicotyledonous weeds can be killed (creeping thistle, hogweed, and centaurea). Grain crops are treated in the tillering stage.

Plants that are sensitive to the action of 2,4-D include cotton and sunflower plants, fruit trees (apple, pear, plum, cherry, apricot, and peach), and berries (currant, strawberry, gooseberry, and raspberry), as well as deciduous trees and shrubs. The action of the herbicide is weaker on poor soils and in periods of drought; plants raised on rich and moist soils die more quickly. 2,4-D is moderately toxic to animals and humans.

The mechanism of action of 2,4-D has not been conclusively studied. It is known to be rapidly absorbed by plant leaves and to cause expansion of meristematic cells, which leads to the destruction of tissues and to curling and death of the plant. It is comparatively rapidly destroyed by microorganisms in the soil and does not accumulate.


Mel’nikov, N. N., and lu. A. Baskakov. Khimiia gerbitsidov i reguliatorov rosta rastenii. Moscow, 1962.
Crafts, A., and W. Robbins. Khimicheskaia bor’ba s sorniakami Moscow, 1964. (Translated from English.)
Mel’nikov, N. N. Khimiia pestitsidov. Moscow, 1968.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Foster-Ehrentreich et al., "Zeptomole-detecting biosensor for alkaline phosphatase in an electrochemical immunoassay for 2,4-dichlorophenoxyacetic acid," International Journal of Computer Vision, vol.
Rothman et al., "Micronucleus frequency and proliferation in human lymphocytes after exposure to herbicide 2,4-dichlorophenoxyacetic acid in vitro and in vivo," Mutation Research, vol.
While some herbicides are naturally supplied (walnut), others are artificial such as 2,4-dichlorophenoxyacetic acid and Atrazine.
The effect of 2,4-dichlorophenoxyacetic acid (2,4-D) at low concentrations on cell cycle duration and sister-chromatid exchange (SCE) frequency was studied using meristem root-tip cells of Garlic (Allium sativum L.) 2,4-D induced a marked prolongation of the cell cycle.
The active ingredient in Citrus Fix[R] is the highly volatile isopropyl ester of 2,4-dichlorophenoxyacetic acid, which is used to prevent fruit drop in citrus.
In addition, 2,4-dichlorophenoxyacetic acid (2,4-D) and kinetin are included at 4.5 [micro]m and YY-ZZ [micro]m, the concentration of
Approximately 1800 acres were sprayed with a tank-mix of 4 ounces of Plateau, and 16 to 32 ounces of 2,4-dichlorophenoxyacetic acid, a herbicide, was added to help control unsightly broadleaf weeds.
Herbicides and pesticides include 2,4-dichlorophenoxyacetic acid, 2,4,5-trichlorophenoxyacetic acid, sodium arsenite, warfarin, and carbaryl.
The sample records look like this: 2,4-DICHLOROPHENOXYACETIC ACID -ENVIRONMENTAL ASPECTS 2,4-Dichlorophenoxyacetic acid (2,4-D) -environmental aspects - Geneva : World Health Organization, 1989.
Sterilized seeds were cultured on solidified medium containing, MS basal medium (Murashige and Skoog, 1962), 3% sucrose, 0.3% gelrite agar, 5 mg/L NAA (a-naphthaleneacetic acid) and 1 mg/L 2, 4-D (2,4-dichlorophenoxyacetic acid) for callus induction.
Kamat, "Hydroxyl radical's role in the remediation of a common herbicide, 2,4-dichlorophenoxyacetic acid (2,4-D)," The Journal of Physical Chemistry A, vol.