1918-00-9 Hazards Identification
Pictogram(s):
Signal:
Danger
GHS Hazard Statements:
H302: Harmful if swallowed [Warning Acute toxicity, oral]
H318: Causes serious eye damage [Danger Serious eye damage/eye irritation]
H412: Harmful to aquatic life with long lasting effects [Hazardous to the aquatic environment, long-term hazard]
Precautionary Statement Codes:
P264, P264+P265, P270, P273, P280, P301+P317, P305+P354+P338, P317, P330, and P501
Hazard Classes and Categories:
Acute Tox. 4 *
Eye Dam. 1
Aquatic Chronic 3
Acute Tox. 4 (100%)
Eye Dam. 1 (99.76%)
Acute Tox. 4 (70.19%)
STOT SE 3 (42.07%)
Aquatic Acute 1 (49.04%)
Aquatic Chronic 3 (99.52%)
Acute toxicity - category 4
Eye damage - category 1
Hazardous to the aquatic environment (chronic) - category 3
Hazards Summary:
Oral LD50 (rats) = 757-1707 mg/kg. Dicamba is corrosive to the eyes and can cause skin burns. [EXTOXNET] The following herbicides have an oral LD50 of >1 gm/kg and have little or no acute toxicity in humans: Alachlor, Amitrole, Ammonium sulfamate, Atrazine, Dalapon, Dicamba, Glyphosphate, Monuron, Oryzalin, Picloram, Propanil, Simazine, etc. [LaDou, p. 613]
1918-00-9 Usage
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 academic research and scientific papers
Selective removing method of benzene ring hydroxyl para-bromine and preparation method of dicamba
-
Page/Page column 5-7, (2019/06/05)
The invention provides a selective removing method of benzene ring hydroxyl para-bromine. The method comprises following steps: a compound represented as formula (I) in the description is subjected toa reaction under the alkaline condition and the action of metal powder to remove hydroxyl para-bromine ions, and a compound represented as formula (II) in the description is obtained. The benzene ring hydroxyl para-bromine ions are selectively removed under the alkaline condition and the action of the metal powder, the reaction has higher selectivity, conversion rate and reaction rate are high, and a prepared product has higher purity.
Preparation method of dicamba
-
Paragraph 0014-0019, (2019/01/23)
The invention relates to a preparation method of dicamba. The method comprises the following steps: preparing 2, 5-dichlorobenzoic acid as a starting raw material; further esterifying with methyl alcohol in an acidic condition; processing to obtain a product; further substituting with bromine under the effect of aluminum tribromide; reacting the obtained product with methyl alcohol under the effect of a catalyst; processing; and further hydrolyzing the obtained product to obtain the final product, namely dicamba. Compared with a traditional synthesizing method, the method has the advantages that few synthesizing steps are performed; the reaction process is simple; the reaction temperature is low; the operation safety is improved; the reaction processing in each step is simple, so that thereaction can be conveniently carried out; and the yield is high.
Preparation method of dicamba
-
Paragraph 0097; 0105; 0110; 0115; 0120; 0125; 0130; 0134, (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.
A dicamba preparation method (by machine translation)
-
Paragraph 0041-0059, (2019/06/05)
The invention provides a method for preparing dicamba, comprises the following steps: A) 3, 6 - II [...] and halogenated methane in water and methanol in mixed solvent of the etherification reaction, to obtain 3, 6 - dichloro - 2 - methoxybenzoic acid methyl ester; B) distilled to remove the methanol; C) after the distillation system layered, organic phase distillation, to obtain baphia methyl ester; D) baphia methyl ester by the alkaline hydrolysis, acidification, drying, get baphia. The invention water and methanol mixed solvent as 3, 6 - II [...] etherification reaction solvent, reaction after first distilled to remove the methanol, then distillation baphia methyl ester, in order to distill and craft has replaced the traditional preparation method recrystallization process, and omits the decoloring this process, compared with the traditional process, the obtained baphia the color of the product is pure white, inch high, and improves the working environment on the site workers, more environment-friendly, alkaline hydrolysis process of the less water, the economical efficiency, technical and environmental protection, improves the stability of the product. (by machine translation)
A catalytic oxidation of the synthesis of the herbicide dicamba 2 - methoxy - 3, 6 - II [...] method
-
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 3,6-dichloro-2-bromotoluene and dicamba
-
, (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-bromotoluene is subjected to a chlorination reactionin chlorosulfonic acid or concentrated sulfuric acid, and 3,6-dichloro-2-bromotoluene is obtained; S2), 3,6-dichloro-2-bromotoluene is subjected to an oxidation reaction and a methoxylation reaction in sequence, and dicamba is obtained. Compared with the prior art, 3,6-dichloro-2-bromotoluene is obtained from 2-bromotoluene after the directional chlorination reaction, and dicamba can be obtained by the oxidation reaction and the methoxylation reaction. The methods have the advantages of easily available raw materials, low comprehensive cost, high methoxylation reaction selectivity, high totalyield, stable product quality and simple process, and facilitate industrial implementation.
Preparation methods of 2-bromo-3,6-dichlorobenzoic acid and dicamba
-
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.
A new process to prepare 3,6-dichloro-2-hydroxybenzoic acid, the penultimate intermediate in the synthesis of herbicide dicamba
Walker, Daniel P.,Harris, G. Davis,Carroll, Jeffery N.,Boehm, Terri L.,McReynolds, Matthew D.,Struble, Justin R.,van Herpt, Jochem,van Zwieten, Don,Koeller, Kevin J.,Bore, Mangesh
, p. 1032 - 1036 (2019/03/17)
Glyphosate [N-(phosphonomethyl)glycine] is a broad spectrum, post-emergent herbicide that is among the most widely used agrochemicals globally. Over the past 30 years, there has been a development of glyphosate-resistant weeds, which pose a significant challenge to growers and crop scientists, resulting in lower crop yields and increased costs. 3,6-Dichloro-2-methoxybenzoic acid (dicamba) is the active ingredient in XtendiMax a standalone herbicide developed by Bayer Crop Science to control broadleaf weeds, including glyphosate-resistant species. 3,6-Dichloro-2-hydroxybenzoic acid (3,6-DCSA) is the penultimate intermediate in the synthesis of dicamba. Existing dicamba manufacturing routes utilize a high temperature, high pressure Kolbe-Schmitt carboxylation to prepare 3,6-DCSA. Described in this Letter is a new, non-Kolbe-Schmitt process to prepare 3,6-DCSA from salicylic acid in four chemical steps.
NOXIOUS ARTHROPOD CONTROL AGENT CONTAINING AMIDE COMPOUND
-
, (2017/08/26)
An object of the present invention is to provide a compound having the controlling activity on a noxious arthropod, and a noxious arthropod controlling agent containing an amide compound of formula (I): wherein X represents a nitrogen atom or a CH group, p represents 0 or 1, A represents a tetrahydrofuranyl group or the like, R1, R2, R3, R4, R5, R6 and R7 represent a hydrogen atom or the like, n represents 1 or 2, Y represents an oxygen atom or the like, m represents any integer of 0 to 7, and Q represents a C1-8 chain hydrocarbon group optionally having a phenyl group or the like, has the excellent noxious arthropod controlling effect.
Synthesis method for raw material drugs of dicamba
-
Paragraph 0022, (2018/01/12)
The invention relates to a synthesis method for raw material drugs of dicamba. The synthesis method for the raw material drugs of dicamba comprises the following steps: taking 2,5-dichlorophenol as a starting material, carrying out esterification under the actions of an organic solvent and an organic esterification reagent to generate 2,5-dichlorophenol acetate; dissolving 2,5-dichlorophenol acetate in the organic solvent and adding a catalyst to generate Fries rearrangement, thus generating 3,6-dichloro-2-hydroxyacetophenone; making 3,6-dichloro-2-hydroxyacetophenone react with a methylating reagent under the action of an acid-binding agent to obtain 3,6-dichloro-2-methylacetophenone; synthesizing dicamba (3,6-dichloro-2-methoxybenzoic acid) under the action of 3,6-dichloro-2-methylacetophenone. The synthesis method for the raw material drugs of dicamba disclosed by the invention is simple in process, highly available in raw materials and the catalyst, low in cost, simple in post-treatment operation, low in environmental pollution, high in safety of reaction operation, high in reaction yield, good in product quality and favorable for industrialization.
