Benzoic acid herbicides

Another case of high nitrosamine concentration in chlorinated phenoxy- and benzoic acid herbicides was resolved by the elimination by the manufacturer of nitrite salts in the formu-... 

Teratogenic (fetus deforming) effects on rats and mice were reported for 2,4,5-T and the isooctyl ester of 2,4-D, while mortality and physical abnormalities were shown to increase in chick embryos of gamebird eggs sprayed with 2,4-D at rates commonly used in field applications [153,166]. The most extensively used halo-genated benzoic acid herbicides are Chloramben and Dicamba. 

There is little published information of interest to carbohydrate chemists concerning the benzoic acid herbicides. The predominant member, 2,3,6-trichlorobenzoic acid, inhibited uptake and utilization109 of acetate-14C. It shows some auxin-like properties, whereas 2,3,5-triiodobenzoic acid appears to block the transport of natural and synthetic auxins, and has often been termed an antiauxin. The triiodo compound inhibited oxygen (86% at... 

Uses In pure form, dicamba is a white crystalline solid. The technical acid is a pale buff crystalline solid. Dicamba is a benzoic acid herbicide that is used for the control of infestation on leaves and soil. Dicamba controls annual and perennial broadleaf weeds in grain crops and grasslands, and is used to control brush and bracken in pastures. It kills broadleaf weeds before and after they sprout. Legume weeds are killed by dicamba. In combination with a phenoxyalkanoic acid or other herbicides, dicamba is used in pastures, rangeland, and noncrop areas such as fencerows and roadways to control weeds.2,17... 

The herbicides resemble and mimic auxins in the activity. They compete with natural auxins, cause abnormal elongation at the growing terminals, tissue proliferation, induce adventitious roots, and modify the arrangement of leaves and other organs. These herbicides act in the same way as the chloro-phenoxy acids (2,4-D and relatives) however, the specific mechanism of action of the benzoic acid herbicides is unknown. 

The most selective member of the benzoic acid herbicides is 3,6-dichloro-2-methoxy-benzoic acid (dicamba, 4), (Sterry, 1961 Velsicol Chemical Co., 1974). 

As mentioned before, dicamba has much greater selectivity than the other benzoic acid herbicides. It is also active against phenoxy-resistent weeds. It is selective in small grains, maize, sugar cane, perennial seed grasses, turf and noncrop land. Its oil-soluble ester is used as a brush-killer. 

Pesticides, such as benzoic acid herbicides, organophosphates, carbamates, methoxy-i -triazines, phenylureas, and phenoxyalkanoates, have an ether linkage or an alkoxy group. 

Muslih R.K. and LinscotFlT.L., 1977. Regulation of lipid biosynthesis in soybeans by two benzoic acid herbicides. Plant Physiol. 730-735. 

Benzaldehyde. Annual production of ben2aldehyde requires ca 6,500—10,000 t (2-3 x 10 gal) of toluene. It is produced mainly as by-product during oxidation of toluene to benzoic acid, but some is produced by hydrolysis of ben2al chloride. The main use of ben2aldehyde is as a chemical intermediate for production of fine chemicals used for food flavoring, pharmaceuticals, herbicides, and dyestuffs. 

Nearly all of the benzal chloride produced is consumed in the manufacture of benzaldehyde. Benzaldehyde (qv) is used in the manufacture of perfume and flavor chemicals, dyes, and pharmaceuticals. The principal part of benzotrichloride production is used in the manufacture of benzoyl chloride (see Benzoic acid). Lesser amounts are consumed in the manufacture of benzotrifluoride, as a dyestuff intermediate, and in producing hydroxybenzophenone ultraviolet light stabilizers. Benzotrifluoride is an important intermediate in the manufacture of herbicides, pharmaceuticals, antimicrobial agents, and the lampreycide, 4-nitro-3-(trifluorometh5l)phenol [88-30-2]. 

The 0- and -monochloro- and 2,4- and 3,4-dichlorobenzotrichlorides are iatermediates ia the manufacture of the corresponding chlotinated benzoic acids and benzoyl chlorides. Fluotination of the chlotinated benzotrichlorides produces the chlotinated benzotrifluorides, iatermediates ia the manufacture of dinitroaniline and diphenyl ether herbicides (76). 

Incorporation of some xenobiotics (herbicides) into soil humus-complexes occurs via pathways analogous to those for incorporation of naturally occurring phenolic and benzoic acids and do indeed involve phenolic and humus-like constituents... 

Benzoic acid, a common food preservative, may be a suitable substrate to achieve biostimulation. It is a relatively inexpensive, harmless aromatic compound that has been previously used in analogue enrichment1 schemes to enhance biodegradation of the aromatic herbicide, 2,3,6-trichlorobenzoic acid (2,3,6-TBA) [336]. Benzoate ion is also an intermediate in the toluene pathway and it can induce related enzymes involved in the degradation of toluene and m-and p-xylenes [336]. In addition, the anionic nature of benzoic acid would minimize its retardation and facilitate its distribution when injected into an... 

Determination of preservatives (sorbic and benzoic acid, parabens) in food products Determination of phenylurea herbicide residues in vegetables and vegetable processed food Separation of flavonoids from extracts of Adinandra nitida leaves... 

Soil. The major soil metabolite is 2,6-dichlorobenzamide which degrades to 2,6-dichloro-benzoic acid. The estimated half-lives ranged from 1 to 12 months (Hartley and Kidd, 1987). Under field conditions, dichlobenil persists from 2 to 12 months (Ashton and Monaco, 1991). The disappearance of dichlobenil from a hydrosol and pond water was primarily due to volatilization and biodegradation. The times required for 50 and 90% dissipation of the herbicide from a hydrosol were approximately 20 and 50 d, respectively (Rice et al., 1974). Dichlobenil has a high vapor pressure and volatilization should be an important process. Williams and Eagle (1979) found... 

Isoxaflutole is an isoxazole herbicide that, in the presence of hypochlorite, hydrolyzed to a stable and phytotoxic metabolite, diketonitrile. This intermediate further degraded to yield benzoic acid as the major end product, which is nonphytotoxic [112]. 

Furthermore, the use of Ralstonia eutropha JMP134-containing sensors for the determination of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) has been described [118,121]. This sensor was sensitive to 2,4-D and 2,4,5-T (2,4,5-trichlorophenoxyacetic acid) with a detection Emit of 40 mg 1 with a response time of 15 s. Moreover, catechol, benzoic acid, and sahcylaldehyde caused higher signals, but no or very little signal was obtained for phenol, biphenyl, and the usual substrates such as glucose, fructose, ethanol, and acetate. 

Yu, L., Qin, W., and Li, S. F. Y, Ionic liquids as additives for separation of benzoic acid and chlorophenoxy acid herbicides by capillary electrophoresis. Anal. Chim. Acta, 547,165-171,2005. 

More than 130 different organic chemicals are currently employed as herbicides in the U.S. All of the main families of organic compounds are represented aromatic, aliphatic, and heterocyclic. Herbicidal activity is found in a variety of classes of compounds haloaliphatic, phenoxy, and benzoic acids carbamates dinitroanilines acetanilides amino triazines quaternary pyridinium salts uracils and ureas. A few selected key examples are reviewed below. 

Chloramben, a benzoic acid derivative introduced by Amchem in 1958, is a selective preemergence herbicide (Fig. 3). It is used principally in soybeans, corn, and peanuts. 

Benzoic acid and amide—they represent a class of herbicides with a soil persistence of about lyr... 

Solar light absorption by the adsorbate may induce chemical changes in the molecule depending on its chemical nature. This process may be an important decomposition route for herbicides showing absorption spectra at A, > 295 nm. Heterocyclic N-containing compounds, phenoxy acids, dinitroanilines, propanil (S -dichloropropionanilide) and benzoic acids are very sensitive to photodecomposition. 

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