Pesticides 2.4- dichlorophenoxyacetic acid

Uses A chemical intermediate in the manufacture of the pesticide 2,4-dichlorophenoxyacetic acid (2,4-D) and other compounds for use as germicides, antiseptics, and seed disinfectants. 

Michel Jr., F.C., Reddy, C.A., and Forney, L.J. 1995. Microbial degradation and humification of the lawn care pesticide 2,4-dichlorophenoxyacetic acid during the composting of yard trimmings. Applied Environmental Microbiology, 61 2566-71. 

Another widely used pesticide, 2-4 dichlorophenoxyacetic acid (2,4-D), was detected with an SPR immunosensor by Gobi et al. [25]. They used inhibition assay and a sensor chip on which the conjugate of BSA and 2,4-D derivative was physisorbed. The detection was performed with monoclonal antibodies in phosphate buffer saline (PBS) using a commercial SPR-20 instrument (from DKK-TOA, Japan). A detection range of 0.5ngmL to 1 p,gmL and a detection time of 20 min were achieved. Regeneration of the sensor for up to 20 detection cycles was performed using pepsin (10 p.g mL ). 

Prado, A.G.S., Airoldi, C. 2(XX). Immobilization of the pesticide 2,4-dichlorophenoxyacetic acid on a silica gel surface. Pest Management Science 56(5) 419-424. 

Finally, the substitution of Pt by BDD leads to a dramatic enhancement of the oxidation ability of the Fenton-based EAOPs, as observed for the pesticide 2,4-dichlorophenoxyacetic acid in Fig. 2. At present, BDD is the best anode material to oxidize organic pollutants, since it yields a high concentration of physisorbed hydroxyl radicals (BDD( OH)) at a very positive anode potential from reaction (7). Therefore, in the EF with BDD, the refractory organic molecules and their complexes with metal ions can be oxidized by the combined action of BDD( OH) formed at the anode and OH produced in the bulk. 

For a given pesticide which undergoes hydrolysis, any or all of these hydrolytic pathways may be relevant at various pH s. Organophosphorothioates, for example, have measurable neutral and alkaline hydrolysis rate constants (7). Esters of 2,4-dichlorophenoxyacetic acid (2,4-D), on the other hand, hydrolyze by acid and alkaline catalyzed reactions, but have extremely small neutral hydrolysis rate constants ( ). Thus, any study of the hydrolysis of sorbed pesticides must be prefaced by an understanding of the hydrolytic behavior of individual pesticides in aqueous solution. 

Our discussion of pesticides has focused primarily on insecticides. In the United States the primary use of pesticides is in the form of herbicides, those pesticides used to control weeds. Approximately 70% of the pesticides used in the United States are herbicides and 20% are insecticides. The use and development of herbicides parallels that of insecticides. The first herbicides were inorganic metal compounds and salts. During World War II organic herbicides were synthesized and their use increased dramatically. One of the first major classes of herbicides synthesized in the mid-1940s was phenoxyaliphatic acids. As this name implies, the phenoxyaliphatic acids contain the benzene ring, oxygen, and an aliphatic acid. The two most common phenoxyaliphatic acids are 2,4 dichlorophenoxyacetic acid, called 2,4-D and 2,4,5 trichlorophenoxyacetic acid, known as 2,4,5-T (Figure 18.10). The numbers in these... 

US Environmental Protection Agency (2005) 2, 4-D (2,4-Dichlorophenoxyacetic Acid) Reregistration Eligibility Decision (RED) Document, document number EPA 738-R-05-002, US Environmental Protection Agency Office of Prevention, Pesticides and Toxic Substances, Washington, DC. 

Dichlorophenol and 2,4,5-trichlorophenol have been used in the synthesis of phenoxy acid herbicides, including 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-tri-chlorophenoxyacetic acid (2,4,5-T). 2,4,5-Trichlorophenol has also been used as a fungicide and a bactericide. 2,4,6-Trichlorophenol has been used as a pesticide. 2,3,4,6-Tetra-chlorophenol has been used as a fungicide (Lewis, 1993 Verschueren, 1996). Chlorophenols have also been formulated and used as salts in some applications. 

Samples are transferred to a separatory funnel, surrogates are added, and an immiscible solvent (dichloromethane, hexane, etc.) is added. The liquids are shaken vigorously for a few minutes and then allowed to rest until a separation between the two phases occurs. The solvent is removed and the extraction process is repeated twice more. The extracts are combined, dried over anhydrous sodium sulphate, and processed further (cleanup) as required. Some laboratories have automated this tedious procedure by performing extractions in bottles. In this case, solvent and water are placed in a bottle and rotated (windmill rotators) or shaken (platform shakers) for 1—2 h. The lack of vigorous shaking is replaced by an extended time for extraction. Liquiddiquid extraction is used for all semivolatile analysis (hydrocarbons >C12, PAH, pesticides, PCB, dioxins). By lowering the pH, extraction of phenols (pentachlorophenol) and acidic compounds (2,4-dichlorophenoxyacetic acid—2,4-D) will be enhanced. Increasing the pH will increase extractability of basic (aromatic amines) and neutral compounds (PAH). 

Badellino, C., Rodrigues, C. A. and Bertazzoli, R. (2006) Oxidation of pesticides by in situ electrogenerated hydrogen peroxide Study for the degradation of 2,4-dichlorophenoxyacetic acid. J. Hazard. Mater. B137, 856-864. 

As Table I illustrates, the chemical classes represented by the pesticides studied include thiophosphates [0,0-diethyl-o-p-nitrophenyl phos-phorothioate], carbamates [1-naphthyI-N-methylcarbamate], dinitrophe-nols [2,4-dinitro-o-sec-butylphenol and 2,4-dinitro-o-cyclohexylphenol], and chlorophenoxy acids [2,4-dichlorophenoxyacetic acid, 2,4,5-trichloro-phenoxyacetic acid, and 2-(2,4,5-trichlorophenoxy)propionic acid]. In addition, a number of molecularly related nitrophenols have been studied to establish the effects of molecular geometry and substituent groups on adsorption of pesticide-type materials. 

Other factors influence the magnitude of the effect of exposure misclassification on estimates of association between exposures and disease. The effect depends not only on the extent of exposure misclassification, but also on the prevalence of exposure in the population studied. Since pesticide exposure prevalence may differ in different populations and is certainly different in general population stndies when compared to studies in farming communities, the performance of exposnre assessment techniques will vary according to the study context. The specificity determines the bias in risk-ratio situations with a low exposure prevalence. Thus, a poor sensitivity, for instance, the one reported by Arbuckle et al. (2002) for 2,4-dichlorophenoxyacetic acid (2,4-D), may not be problematic in a general population or case-control study, as long as the specificity is sufficiently high. 

Nash RG, Kearney PC, Maitlen JC, 5ell CR, Fertig 5N. Agricultural applicators exposure to 2, 4-Dichlorophenoxyacetic acid. In Pesticide residues and exposure. Plimmer JR, editor. AC5 symposium series 182,1982, Chap 10 119-132. 

The principle of making depot preparations by esterification is widely applied not only to steroid hormones, but also to other drugs (e.g vitamin K, the tranquillizer fluphenazine, and the antimalarial amodiaquine (Fig. 35)158,159> and in the field of pesticides to the weedkiller dichlorophenoxyacetic acid. 

Pesticide uses Exemplars Herbicides 2,4-dichlorophenoxyacetic acid (2,4-D), 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), dicamba, mecoprop, 2-(2-methyl-4-chloro-phenoxy) propionic acid (MCPP)... 

Pesticides may be tracked into the indoor environment after a certain outdoor apphcation [18, 19] or through transport from the workplace to the home (para-occupational or take-home exposure). Collection of floor dust both prior to and after lawn-apphed 2,4-dichlorophenoxyacetic acid (2,4-D), indicated that turf residues are transported indoors [20]. Carpet dust levels of 2,4-D and dicamba and carpet surface dislodgeable residue levels were highly correlated with turf dislodgeable residue levels [21]. 

PPARa activators are a unique class of chemical carcinogens that induce peroxisome proliferation and increase the incidence of Uver tumors in rats and/or mice. These include several hypohpidemic drugs (e.g., WY-14,643, gemfibrozil, fenofibrate, bezafibrate, and ciprofibrate) and environmentally relevant compounds such as phthalates or their metabolites (e.g., di-(2-ethylhexyl) phthalate (DEHP), di-(2-ethylhexyl) adipate (DEHA), diisononyl phthalate (DINP), or 2-ethylhexanol (2-EH)), pesticides (e.g., 2,4-dichlorophenoxyacetic acid, diclofopmethyl, haloxyfop, lactofen, oxidiazon), solvents (e.g., perchloroethylene, trichloroethylene), and other industrial chemicals (e.g., HCFC-123, PFOA) (smnmarized in Klaunig etal. (2003)). 

Dichlorophenoxyacetic acid, sodium salt Diconirt Diconirt D Dikonirt Dikonirt D EINECS 220-290-4 EPA Pesticide Chemical Code 030004 Fernoxene Fernoxone Hormit Pielik E Pielika Sodium 2,4-D Sodium 2,4-dichlorophenoxyacetate Spray-hormite Spritz-hormit U-46-D-Fluid. Herbicide, Registered by EPA as a herbicide and fungicide. Aquacide Co. Farnam Companies Inc. Nufarm Americas Inc Riverdale Chemical Co. 

Amylopectins. — The effects of acrylamide graft copolymerization on the solution properties of amylopectin have been discussed. Amylopectin has been dyed with DyAmyl-L and used in this form as a substrate for the assay of a-amylase. Amylopectin has been treated with isocyanate derivatives of 4-amino-( 1,1-dimethyl ethyl)-3-(methylthio)-l,2,4-triazin-5(4/f)-one ( metribuzin ) or acid chloride derivatives of 2,4-dichlorophenoxyacetic acid ( 2,4-D ) and 2,2-dichloropropionic acid ( dalapon ), to produce controlled-release polymeric pesticide systems. The solvent system utilized for these reactions, a lithium chloride or bromide salt in AW-dimethylacetamide, allows dissolution of the reactant salt and facilitates analysis of the polymer product by such techniques as i.r., U.V., and n.m.r. spectroscopies and gel permeation chromatography. Derivatives of other naturally occurring polysaccharides, including amylopectin, cellulose, chitin, and dextran, were also prepared. 

D 2,4-dichlorophenoxyacetic acid (2,4-dichlorophenoxyethanoic acid) a synthetic auxin used as a weedkiller of broad-leaved weeds. See pesticide. 

In another study by Dennis et al. [141], the DNA microarray technology was used to monitor the expression of catabolic genes related to 2,4-dichlorophenoxyacetic acid (2,4-D) degradation within pme and mixed cultures of the 2,4-D-degrading bacterium Ralstonia eutropha JMP134. With this technique, it was shown that two of five 2,4-D catabolic genes were induced upon addition of the pesticide. The study demonstrated the potential of DNA microarrays for the detection of functional genes in complex environmental systems. 

---