1918-00-9 Usage
Description
Dicamba, a benzoic acid derivative, is a broad-spectrum herbicide used to control various types of weeds. It is a white solid dissolved in a liquid carrier, which is water emulsifiable. As a synthetic mimic of natural auxin, a plant hormone, Dicamba stimulates abnormal plant growth, leading to nutrient exhaustion and plant death. The primary hazard of Dicamba is its threat to the environment, as it can easily penetrate the soil and contaminate groundwater and nearby streams. It can cause illness through inhalation, skin absorption, and/or ingestion.
Uses
1. Agricultural Uses:
Used in Cereal Crops:
Dicamba is used as a selective, systemic pre-emergence and post-emergence herbicide to control annual and perennial broad-leaved weeds, chickweed, mayweed, and bindweed in cereals and other related crops.
Used in Corn, Sorghum, and Sugarcane:
Dicamba is employed for the preand post-emergence control of annual and perennial broadleaf weeds in corn (Zea mays), sorghum, and sugarcane (Saccharum spp.).
Used in Asparagus and Turf:
Dicamba is used in asparagus (Asparagus officinalis) and turf for weed control.
Used in Pastures, Hay, Rangeland, and Grass-Seed Crops:
Dicamba is utilized to control weeds in pastures, hay, rangeland, and grass-seed crops, as well as non-croplands.
2. Combination with Other Herbicides:
Dicamba is frequently applied with other herbicides, such as atrazine, glyphosate, imazethapyr, ioxynil, and mecoprop, to enhance weed control.
3. Control of Specific Weeds:
Dicamba is used to control weeds like dock, bracken, and brush, as well as annual and perennial rose weeds in grain crops and highlands.
4. Environmental Considerations:
Immediate steps should be taken to limit the spread of Dicamba to the environment, as it poses a threat to the environment and can contaminate groundwater and nearby streams.
Resistance
Some farmers and researchers have expressed concern about?herbicide resistance?after the introduction of?resistant crops.In the laboratory, researchers have demonstrated weed resistance to dicamba within three generations of exposure.Similar herbicide resistant weeds arose after the introduction of?glyphosate-resistant crops (marketed as 'Roundup Ready').Some weed species, like?Amaranthus palmeri, have developed resistance to dicamba. Dicamba resistance in?Bassia scoparia?was discovered in 1994 and has not been explained by common modes of resistance such as absorption, translocation, or metabolism.
References
Grossmann, Klaus. "Mode of action of auxin herbicides: a new ending to a long, drawn out story." Trends in Plant Science 5.12(2000):506-8.
Grossmann, Klaus. "Auxin herbicides: current status of mechanism and mode of action." Pest Management Science 66.2(2010):113–120.
Gleason, Cynthia, R. C. Foley, and K. B. Singh. "Mutant Analysis in Arabidopsis Provides Insight into the Molecular Mode of Action of the Auxinic Herbicide Dicamba." Plos One 6.3(2011):e17245.
Reactivity Profile
A halogenated benzoic acid derivative. Carboxylic acids donate hydrogen ions if a base is present to accept them. They react in this way with all bases, both organic (for example, the amines) and inorganic. Their reactions with bases, called "neutralizations", are accompanied by the evolution of substantial amounts of heat. Neutralization between an acid and a base produces water plus a salt. Carboxylic acids with six or fewer carbon atoms are freely or moderately soluble in water; those with more than six carbons are slightly soluble in water. Soluble carboxylic acids dissociate to an extent in water to yield hydrogen ions. The pH of solutions of carboxylic acids is therefore less than 7.0. Many insoluble carboxylic acids react rapidly with aqueous solutions containing a chemical base and dissolve as the neutralization generates a soluble salt. Carboxylic acids in aqueous solution and liquid or molten carboxylic acids can react with active metals to form gaseous hydrogen and a metal salt. Such reactions occur in principle for solid carboxylic acids as well, but are slow if the solid acid remains dry. Even "insoluble" carboxylic acids may absorb enough water from the air and dissolve sufficiently in Dicamba to corrode or dissolve iron, steel, and aluminum parts and containers. Carboxylic acids, like other acids, react with cyanide salts to generate gaseous hydrogen cyanide. The reaction is slower for dry, solid carboxylic acids. Insoluble carboxylic acids react with solutions of cyanides to cause the release of gaseous hydrogen cyanide. Flammable and/or toxic gases and heat are generated by the reaction of carboxylic acids with diazo compounds, dithiocarbamates, isocyanates, mercaptans, nitrides, and sulfides. Carboxylic acids, especially in aqueous solution, also react with sulfites, nitrites, thiosulfates (to give H2S and SO3), dithionites (SO2), to generate flammable and/or toxic gases and heat. Their reaction with carbonates and bicarbonates generates a harmless gas (carbon dioxide) but still heat. Like other organic compounds, carboxylic acids can be oxidized by strong oxidizing agents and reduced by strong reducing agents. These reactions generate heat. A wide variety of products is possible. Like other acids, carboxylic acids may initiate polymerization reactions; like other acids, they often catalyze (increase the rate of) chemical reactions.
Trade name
BANEX?; BANLEN?; BANVEL?;
BANVEL 4S?; BANVEL 4WS?; BANVEL CST?;
BANVEL HERBICIDE?; BANVEL II HERBICIDE?;
BRUSH BUSTER?; BUSHWHACKER?; CADENCE?;
CASWELL No. 295?; CLARITY?; COMPOUND
B DICAMBA?; DIANATE?; DISTINCT?;
DYVEL?; FALLOWMASTER?; FLOWMASTER?;
GORDON’S TRIGUARD?; GORDON’S TRI-MEC?;
MARKSMAN?; MEDIBEN?; NORTHSTAR?;
SUMMIT?; TARGET?; TRACKER?; TROOPER?;
VANQUISH?; VELSICOL 58-CS-11?; VELSICOL
COMPOUND R?; WEEDMASTER?; YUKON?
Biochem/physiol Actions
Dicamba is a broad leaf growth regulator that mimics plant growth auxins. Dicamba is used as a herbicide and is effective against glyphosate-resistant (GR) giant ragweed.
Pharmacology
Dicamba is highly mobile in soils
and will leach or move upward depending on the flux of
the soil water. Adsorption to soils is generally limited,
although a few studies using acidic kaolinite and muck
soils showed that dicamba was adsorbed to these soils.
Adsorption of dicamba is greatest at low soil pHs and
is minimal at pHs greater than 6.0. Because dicamba is
highly water soluble, it is reasonable to expect that some
loss may occur via soil water runoff from the application
zone. However, studies conducted by Trichelle et al. (44)
showed that such losses were minimal, i.e., less than 5.5%
of applied. The rate of dicamba volatilization is not clear,
although it is likely that it does occur to some extent.
On planchets, approximately 50% of applied dicamba
volatilized over a period of 11 weeks. The significance
of this result is questionable, because in a similar study
using soil, there was no appreciable volatilization (45).
Safety Profile
Moderately toxic by
ingestion. Mutation data reported. When
heated to decomposition it emits toxic
fumes of Cl-.
Environmental Fate
Biological. In a model ecosystem containing sand, water, plants and biota, dicamba
was slowly transformed to 5-hydroxydicamba (10% after 32 days) which slowly underwent
decarboxylation (Yu et al., 1975).
Soil. Smith (1974) studied the degradation of 14C-ring- and 14C-carboxyl-labeled
dicamba in moist prairie soils at 25°C. After 4 weeks, >50% of the herbicide degraded to
the principal products 3,6-dichlorosalicylic acid and carbon dioxide (Smith, 1974).
The half-lives for dicamba in soil incubated in the laboratory under aerobic conditions
ranged from 0 to 32 days (Altom and Stritzke, 1973; Smith, 1973, 1974; Smith and
Cullimore, 1975). In field soils, the half-lives for dicamba ranged from 6 to 10 days with
an average half-life of 7 days (Scifres and Allen, 1973; Stewart and Gaul, 1977). The
mineralization half-lives for dicamba in soil ranged from 147 to 309 days (Smith, 1974;Smith and Cullimore, 1975). In a Regina heavy clay, the loss of dicamba was rapid.
Approximately 10% of the applied dosage was recovered after 5 weeks. At the end of 5
weeks, approximately 28% was transformed to 3,6-dichlorosalicylic acid and carbon
dioxide (Smith, 1973a).
Groundwater. According to the U.S. EPA (1986) dicamba has a high potential to leach
to groundwater.
Plant. Dicamba is hydrolyzed in wheat and Kentucky bluegrass plants to 5-hydroxy-
2-methoxy-3,6-dichlorobenzoic acid and 3,6-dichlorosalicylic acid at yields of 90 and 5%,
respectively. The remaining 5% was unreacted dicamba (Broadhurst et al., 1966). Dicamba
was absorbed from treated soils, translocated in corn plants and then converted to 3,6-
dichlorosalicylic acid, p-aminobenzoic acid and benzoic acid (Krumzdorf, 1974).
Photolytic. When dicamba on silica gel plates was exposed to UV radiation (λ= 254
nm), it slowly degraded to the 5-hydroxy analog and water solubles (Humburg et al., 1989).
Chemical/Physical. Reacts with alkalies (Hartley and Kidd, 1987), amines and alkali
metals (Worthing and Hance, 1991) forming very water-soluble salts.
When dicamba was heated at 900°C, carbon monoxide, carbon dioxide, chlorine,
hydrochloric acid, oxygen and ammonia were produced (Kennedy et al., 1972, 1972a).
Toxicity evaluation
There is very little metabolism of
dicamba in mammals, and most is excreted unchanged
in the urine. For example, rat excreted 96% of ingested
14C-dicamba after 24 hours (46). The acute oral LD50 for
rat is 1707 mg/kg.
Check Digit Verification of cas no
The CAS Registry Mumber 1918-00-9 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 1,9,1 and 8 respectively; the second part has 2 digits, 0 and 0 respectively.
Calculate Digit Verification of CAS Registry Number 1918-00:
(6*1)+(5*9)+(4*1)+(3*8)+(2*0)+(1*0)=79
79 % 10 = 9
So 1918-00-9 is a valid CAS Registry Number.
InChI:InChI=1/C8H6Cl2O3/c1-13-7-5(10)3-2-4(9)6(7)8(11)12/h2-3H,1H3,(H,11,12)
1918-00-9Relevant articles and documents
A catalytic oxidation of the synthesis of the herbicide dicamba 2 - methoxy - 3, 6 - II [...] method
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Paragraph 0030; 0034; 0035, (2019/11/04)
The invention relates to a method for synthetizing a herbicide-dicamba (2-methoxy-3,6-dichloro-salicylic acid) through catalytic oxidation. The method is characterized in that the dicamba is obtained through oxidation of air, oxygen or ozone by taking 2-substituent 3,6-banair as a raw material and adopting a composite catalyst. The method disclosed by the invention has the advantages that the operation is simple, the raw material is easy to obtain, the cost is low, the catalyst can be recycled, and the method is more environment-friendly and is more suitable for industrial production.
Preparation methods of 2-bromo-3,6-dichlorobenzoic acid and dicamba
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Paragraph 0039; 0042-0043; 0046-0050; 0052, (2019/06/05)
The invention provides a preparation method of dicamba. The preparation method comprises the following steps: S1), in the presence of a catalyst, 2-bromobenzoic acid is subjected to a chlorination reaction in chlorosulfonic acid or concentrated sulfuric acid, and 2-bromo-3,6-dichlorobenzoic acid is obtained; S2), 2-bromo-3,6-dichlorobenzoic acid is subjected to a methoxylation reaction, and dicamba is obtained. Compared with the prior art, 2-bromo-3,6-dichlorobenzoic acid is obtained from 2-bromobenzoic acid after the directional chlorination reaction, and dicamba can be obtained by the methoxylation reaction. The methods have the advantages of easily available raw materials, low comprehensive cost, high methoxylation reaction selectivity, high total yield, stable product quality and simple process, and facilitate industrial implementation.
Preparation method of dicamba
-
, (2019/06/05)
The invention provides a preparation method of dicamba. The preparation method comprises the steps as follows: A) salicylic acid and bromine or hydrogen bromide are subjected to a reaction in concentrated sulfuric acid, 5-bromosalicylic acid is obtained; B) 5-bromosalicylic acid and chlorine are subjected to a chlorination reaction, 5-bromo-3,6-dichlorosalycylic acid is obtained; C) 5-bromo-3,6-dichlorosalycylic acid is subjected to a debromination reaction under the alkaline condition and under the action of metal powder, and 3,6-dichlorosalycylic acid is obtained; D) 3,6-dichlorosalycylic acid and halomethane are subjected to an etherification reaction in a mixed solvent of water and methanol, and methyl-3,6-dichloro-2-methoxybenzoate is obtained; E) methanol is removed by distillation;F) a system after distillation is left to stand for laying, an organic phase is distilled, and dicamba methyl ester is obtained; G) dicamba methyl ester is subjected to alkaline hydrolysis, acidification and drying, and dicamba is obtained. The route comprises few steps and has low difficulty, the equipment requirement and investment are lower, continuous production can be realized, no three wastes are produced, and the product yield and purity are higher.
