2.4- Dichlorophenoxy butyric

P 11.8 Evaluating the Sorption of an Organic Anion, 2,4-Dichlorophenoxy-Butyrate, to Negatively Charged Natural Solids... 

In Fig. 11.9c, some sorption data are shown indicating that an organic anion, 2,4-dichlorophenoxy-butyrate (DB ), sorbed to a sediment from water of pH 7.9 despite the sediment s overall negative charge (as evidenced by its CEC of about 140 mmol kg-1 Jafvert, 1990). 

Dichloro-4-nitrobenzenediazonium hydrogen sulfate, 2099 Dichloronitrobenzene, 2096 A A -Dichloropentafluorosulfanylamine, 4054 Dichlorophenol mixed isomers, 2154 4-(2,4-Dichlorophenoxy)butyric acid, 3266 Dichlorophenylborane, 2215... 

D 2,4,5-T Silvex 2.4- DB MCPA Dichlorprop Dicamba (2,4-dichlorophenoxy) acetic acid (2,4,5-trichlorophenoxy) acetic acid (2,4,5-trichlorophenoxy)propionic acid 4-(2,4-dichlorophenoxy) butyric acid (4-chloro-2-methylphenoxy)acetic acid 2-(2,4-dichlorophenoxy)propionic acid 3,6-dichloro-2-methoxybenzoic acid... 

Chemical Name 4-(2,4-dichlorophenoxy)butanoic acid 4-(2,4-dichlorophenoxy)butyric acid... 

Dichlorophenoxy)butyric acid, 3272 tran5-Dichlorotetrapyridinecobalt(lll) chloride, 3802 Diethylaminosulfinyl chloride, 1679... 

In the following example of enzymatic -oxidation, 4-(2,4-dichlorophenoxy)-acetic acid is formed from 4-(2,4-dichlorophenoxy)butyric acid, 4-(2,4-DB) ... 

Dichlorophenoxy)butyric acid is converted in the presence of ATP into dichlorophenoxybutyryl coenzyme A. This acyl-CoA is converted by the electron acceptor flavine adenine dinucleotide (FAD) into dichlorophenoxycrotonyl-CoA. One carbon atom of the unsaturated bond is hydroxilated and dichlorophenoxy- -hydroxybutyric acid-CoA is formed. In certain plants possessing specific /3-oxidase enzyme systems, -ketobutyric acid-CoA is formed from this intermediate compound by the mediation of NAD and NADH in a reaction catalysed by -hydroxyacyl-CoA dehydrogenase. This compound is decomposed by hydrolysis into 2,4-D and acetyl-CoA. 

The chlorophenoxyalkanoic acids constitute yet another economically important group of halogenated aromatic hydrocarbons. They are widely used as herbicides to control dicotyledonous weeds. The most important of them are 2,4-D and its propionic and butyric acid homologs, 4-chloro> 2-methylphenoxyacetic acid (MCPA), and 2,4,5>trichlorophenoxyacetic add (2,4,5-T). In all the cases studied, aerobic biodegradation proceeds by removal of the aliphatic side chain with the formation of the corresponding chlorinated phenoL Thus, formation of 2,4 chlorophenol from both 2,4-D and 4-(2,4-dichlorophenoxy)-butyric acid, 4-chloro-o-cresol from MCPA, and 2,4,5-trichlorophenol from 2,4,5-T has been... 

Dichlorophenoxy) butyric acid y-(2,4-Dichlorophenoxy) butyric acid. See 2,4-DB... 

Benzoic acid /77-Hydroxybenzoic acid o-Hydroxybenzoic acid p-Hydroxybenzoic acid Benzoylformic acid 2-Chlorophenoxyacetic acid 4(2,4-Dichlorophenoxy)-butyric acid Mandelic acid D-Mandelic acid L-Mandelic acid Phenylacetic acid -Phenylpropionic acid Quinic acid Salicylic acid Cinnamic acid... 

Abbreviated names are derived from chemical or common names DDT (dichlorodiphenyltrichloroethane), HCH (1.2.3.4.5.6-hexachlorocyclohexane), PCNB (pentachloronitrobenzene), TCNB (1,2,4,5-tetrachloro-3-nitrobenzene), 2,3,6-TBA (2,3,6-trichlorobenzoic acid), TCA (trichloroacetic acid), 2,4-D [(2,4-dichlorophenoxy)acetic acid], 2,4-DB [4-(2,4-dichlorophenoxy)butyric acid], MCPA [(4-chloro-2-methylphenoxy)acetic acid)], MCPB [(4-chloro-o-tolyloxy)butyric acid)], 2,4,5-T (trolamine or 2,4,5-T-triethylammonium), EPTC (S-ethyIdipropylthiocarbamate), GA3 (gibberellic acid or gibberellin A3). 

Chronoamperometry techniques, in which a potential is applied to the working electrode, have the advantage of isolating in many cases a single reaction, without the complication of other parallel reactions. An example is a method for the detection of organochlorine compounds based on their dechlorination, using GC electrodes modified with protoporphyrin IX cobalt(III) chloride (GC/Cl(ProP)Co) [27]. The results for the 2,4-dichlorophenoxycarboxilic acid (2,4D), 2-(2,4-dichlorophenoxy) propionic acid (2,4-DP), 2-(2,4,5-trichlorophenoxy)propi-onic acid (2,4,5-TP) and 4-(2,4-dichlorophenoxy)-butyric acid (2,4-DB) are shown in Table 1. 

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