Degradation 2,4-dichlorophenol

J.H., and Lee, E.K. (2008) Functionality improvement of fungal lignin peroxidase by DNA shuffling for 2,4-dichlorophenol degradability and HjOj stability. ]. 

Several facts have emerged from our studies with 2,7-DCDD and 2,3,7,8-TCDD. They are not biosynthesized by condensation of chloro-phenols in soils, and they are not photoproducts of 2,4-dichlorophenol. They do not leach into the soil profile and consequently pose no threat to groundwater, and they are not taken up by plants from minute residues likely to occur in soils. Photodecomposition is insignificant on dry soil surfaces but is probably important in water. Dichlorodibenzo-p-dioxin is lost by volatilization, but TCDD is probably involatile. These compounds are not translocated within the plant from foliar application, and they are degraded in the soil. 

Valli K, MH Gold (1991) Degradation of 2,4-dichlorophenol by the lignin-degrading fungus Phanerochaete chrysosporium. J Bacteriol 173 345-352. 

Although the results of experiments on the dechlorination of pentachlorophenol (Bryant et al. 1991) enabled elucidation of the pathways to be elucidated, this study also revealed one of the limitations in the use of such procedures. Detailed interpretation of the kinetics of pentachlorophenol degradation using dichlorophenol-adapted cultures was equivocal due to carryover of phenol from the sediment slurries. 

Both in situ microcosms and laboratory systems were used to compare and evalnate first-order rates of degradation for a range of mixed snbstrates inclnding aromatic hydrocarbons and phenolic compounds (Nielsen et al. 1996). The observed rates were comparable, althongh no systematic differences were observed with the exception of 2,6-dichlorophenol, which was not degraded in the laboratory system. 

Crescenzi et al. developed a multi-residue method for pesticides including propanil in drinking water, river water and groundwater based on SPE and LC/MS detection. The recoveries of the pesticides by this method were >80%. Santos etal. developed an on-line SPE method followed by LC/PAD and LC/MS detection in a simultaneous method for anilides and two degradation products (4-chloro-2-methylphenol and 2,4-dichlorophenol) of acidic herbicides in estuarine water samples. To determine the major degradation product of propanil, 3,4-dichloroaniline, the positive ion mode is needed for atmospheric pressure chemical ionization mass spectrometry (APCI/MS) detection. The LOD of 3,4-dichloroaniline by APCI/MS was 0.1-0.02 ng mL for 50-mL water samples. 

Dorathi PJ, Ranjit KP, Lee C-S (2008) Degradation of 2,4-dichlorophenol in aqueous solution by sono-Fenton method. Korean J Chem Engi 25(1) 112-117... 

Al-Ekabi, H., N. Serpone, E. Pelizzetti, C. Minero, M. A. Fox, and R. B. Draper (1989), "Kinetic Studies in Heterogeneous Photocatalysis. 2. Ti02 Mediated Degradation of 4-Chlorophenol Alone and in a 2,4-Dichlorophenol, and 2,4,5-Trichlorophenol in Air-Equilibrated Aqueous Media," Langmuir 5, 250-255. 

Soil Under aerobic conditions, indigenous microbes in contaminated soil produced pentachlorocyclohexane. However, under methanogenic conditions, a-BHC was converted to chlorobenzene, 3,5-dichlorophenol, and the tentatively identified compound 2,4,5-trichlorophenol (Bachmann et al., 1988). Manonmani et al. (2000) isolated a microbial consortium from sewage and soil that could completely mineralize a-BHC in 14 d at 30 °C. The acclimated consortium could degrade up to 100 mg/L of a-BHC within 72 h at a degradation rate of 58 mg/L-day. 

Larson et al. (1992) studied the photosensitizing ability of 2, 3, 4, 5 -tetraacetylriboflavin to various organic compounds. An aqueous solution containing 2,4-dichlorophenol was subjected to a medium-pressure mercury arc lamp (A >290 nm). The investigators reported that 2, 3, 4, 5 -tetraacetylriboflavin was superior to another photosensitizer, namely riboflavin, in the degradation of 2,4-dichlorophenol and other compounds. Direct photolysis of 2,4-dichlorophenol without any photosensitizer present resulted in a half-life of 21 min. In the presence of ribloflavin and 2, 3, 4, 5 -tetraacetylriboflavin, the half-lives were 6.3 and 4.1 min, respectively. 

Pentachlorophenol degraded in anaerobic sludge to 3,4,5-trichlorophenol, which was reduced to 3,5-dichlorophenol (Mikesell and Boyd, 1985). In activated sludge, only 0.2% of the applied amount was mineralized to carbon dioxide after 5 d (Freitag et al., 1985). 

Smith, A.E. Identification of 2,4 dichloroanisole and 2,4-dichlorophenol as soil degradation prodncts of ring-labelled [ 12,4-... 

Oxidative coupling involves condensation reactions catalyzed by phenol oxidases. In oxidative coupling of phenol, for example, arloxy or phenolate radicals are formed by the removal of an electron and a proton from an hydroxyl group. The herbicide 2,4-D is degraded (Fig. 15.5) to 2,4 dichlorophenol, which can be oxidatively coupled by phenol oxidases (Bollag and Liu 1990). 

Those degradation products which have been identified in our investigations are 1-naphthol from carbaryl, 2,4-D acid and 2,4-dichlorophenol from 2,4-D ester, 2-chloro-2, 6 -diethylacetanilide from alachlor, o,o,oe-trifluro-2-nitro-6-amino-N,N-dipropyl-p-tolu-idine and o,o,o-trifluro-2,6-diamino-N,N-dipropyl-p-toluidine from trifluralin, and a variety of phenols and acids from the degradation of the aromatic solvents used in the formulation of the liquid pesticides as emulsifiable concentrates (41,42). 

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