1.4- dichlorobenzene. degradation

Yadav JS, RE Wallace, CA Reddy (1995) Mineralization of mono- and dichlorobenzenes and simultaneous degradation of chloro- and methyl-substituted benzenes by the white-rot fungus Phanerochaete chryso-sporium. Appl Environ Microbiol 61 677-680. 

For aerobic degradation by Pseudomonas sp. strain P51, which carried out degradation by dioxygenation, the valnes were not significant. In contrast, the isotope enrichment factor (e) for anaerobic dechlorination by Dehalococcoides sp. strain CDBl, which produced 1,3-dichlorobenzene from 1,2,3-trichlorobenzene, was -3.4 ppm, and for 1,2,4-trichlorobenzaene, which produced 1,4-dichlorobenzene, was -3.2 ppm. 

As far as polymer supports for microwave-assisted SPOS are concerned, the use of cross-linked macroporous or microporous polystyrene (PS) resins has been most prevalent. In contrast to common belief, which states that the use of polystyrene resins limits reaction conditions to temperatures below 130 °C [14], it has been shown that these resins can withstand microwave irradiation for short periods of time, such as 20-30 min, even at 200 °C in solvents such as l-methyl-2-pyrrolidone or 1,2-dichlorobenzene [15]. Standard polystyrene Merrifield resin shows thermal stability up to 220 °C without any degradation of the macromolecular structure of the polymer backbone, which allows reactions to be performed even at significantly elevated temperatures. 

Haloarene chromium tricarbonyl complexes are activated to nucleophilic attack by thiolate anions [58, 59]. High yields of the thioethers are obtained under liquiddiquid two-phase conditions, but optimum yields are achieved under soliddiquid conditions. In many cases the thioether is produced directly but, where the reaction mixture contains thioether and its chromium complex, the thioether can be isolated by degradation of the complex with iodine or an excess of the thiol. Both 1,2- and 1,4-dichlorobenzenes yield only monothioethers, even when an excess of thiolate anion is used. In contrast, 1,3-dichlorobenzenes produce a mixture of the mono- and dithioethers [59]. Aryl allyl thioethers have been produced under catalysed Heck reaction conditions from S-allyl thiocarbamates and iodobenzene [60]. 

Groundwater. Nielsen et al. (1996) studied the degradation of 1,2-dichlorobenzene in a shallow,... 

Biological. In activated sludge, <0.1% degraded (mineralized) to carbon dioxide after 5 d (Lreitag et ah, 1985). When 1,4-dichlorobenzene was statically incubated in the dark at 25 °C with yeast extract and settled domestic wastewater inoculum, significant biodegradation with gradual acclimation was followed by a deadaptive process in subsequent subcultures. At a concentration of 5 mg/L, 55, 61, 34, and 16% losses were observed after 7, 14, 21, and 28-d incubation periods, respectively. At a concentration of 10 mg/L, only 37, 54, 29, and 0% losses were observed after 7, 14, 21, and 28-d incubation periods, respectively (Tabak et ah, 1981). 

Bitterfeld, Germany. This bacterium utilized 1,4-dichlorobenzene as the sole source of carbon and energy. Degradation products identified using GC/MS were 3,6-dichloro-c/5-l,2-dihydroxy-cyclohexa-3,5-diene, 3,6-dichlorocatechol, 3,5-dichloromuconic acid, 2-chloromaleylacetic acid, and 2-chloroacetoacrylic acid. 

Biological. Under aerobic conditions, soil microbes are capable of degrading 1,2,3-trichlorobenzene to 1,2- and 1,3-dichlorobenzene and carbon dioxide (Kobayashi and Rittman, 1982). A mixed culture of soil bacteria or a Pseudomonas sp. transformed 1,2,3-trichlorobenzene to 2,3,4-, 3,4,5-, and 2,3,6-trichlorophenol (Ballschiter and Scholz, 1980). 

Spiess, E., Sommer, C., and Gorisch, H. Degradation of 1,4-dichlorobenzene by Xanthobacterilavus 14pl, Appl. Environ. Microbiol, 61(11) 3884-3888, 1995. 

Dichlorobenzene is degraded in the atmosphere by reaction with hydroxyl radicals, with an atmospheric lifetime (theoretically calculated) of about 1 month (Atkinson et al. 1985 Singh et al. 1981). 

Pure cultures of Pseudomonas sp. isolated by selective enrichment from activated sludge were reported to degrade 1,4-dichlorobenzene (Spain and Nishino 1987). These authors reported that the 1,4-dichloro-... 

Schraa G, Boone ML, Jetten MSM, et al. 1986. Degradation of 1,4 dichlorobenzene by alcaligenes sp. strain al75. Applied Environ Microbiol 52(6) 1374-1381. 

Spain JC, Nishino SF. 1987. Degradation of 1,4-dichlorobenzene by a Pseudomonas sp. Appl Environ Microbiol 53 1010-1019. 

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