Nitrobenzene degradation

He Z, JC Spain (1998) A novel 2-aminomuconate deaminase in the nitrobenzene degradation pathways of Pseudomonas pseudoalcaligenes JS 45. J Bacteriol 180 2502-2506. 

Wu J-f, C-y Jiang, B-j Wang, Y-f Ma, Z-p Liu, S-j Liu (2006) Novel partial reductive pathway for 4-chloro-nitrobenzene and nitrobenzene degradation in Comamonas sp. strain CNB-1. Appl Environ Microbiol 12 1759-1765. 

Chunli Z, Jiti Z, Jing W, Jing W, Baocheng Q (2008) Isolation and characterization of a nitrobenzene degrading yeast strain from activated sludge. J Hazard Mat 160 194—199... 

Because nitrobenzene degradation is faster in batch experimental systems than in column studies, a mass-transfer limitation exists therefore, when determining the effectiveness of in situ groundwater treatment systems, hydraulics, mass transfer, and reaction kinetics should be taken into consideration (Burris et al., 1996). 

There is no known mechanism of hydrolysis of nitrobenzene however, photolysis and biodegradation are significant nitrobenzene degradation pathways in water (Callahan et al. 1979 Mabeyetal. 1982). 

Haigler BE, JC Spain (1991) Biotransformation of nitrobenzene by bacteria containing toluene degradative pathways. Appl Environ Microbiol 57 3156-3162. 

He Z, JC Spain (1997) Studies of the catabolic pathway of degradation of nitrobenzene by Pseudomonas pseudoalcaligenes JS45 removal of the amino group from 2-aminomuconic semialdehyde. Appl Environ Microbiol 63 4839-4843. 

Nishino SF, JC Spain (1993) Degradation of nitrobenzene by a Pseudomonas pseudoalcaligenes. Appl Environ Microbiol 59 2520-2525. 

Nishino SF, JC Spain (1995) Oxidative pathways for the degradation of nitrobenzene by Comamonas sp. strain JS 765. Appl Environ Microbiol 61 2308-2313. 

Yang, Y., Ma, J., Qin, Q. and Zhai, X. (2007) Degradation of nitrobenzene by nano-Ti02 catalyzed ozonation. Journal of Molecular Catalysis A Chemical, 267, 41-48. 

This and other work indicates that HC1 is largely undissociated in nitromethane for [HC1]>- 0.015 M and that there is little association either. There is evidence that a corresponding addition occurs to olefins in theimally degraded PVC. Results carried out in a variety of solvents (26) are consistent with elimination of HC1 occurring by a/3 -elimination of the Ex type favored by polar solvents. The same authors showed that at least in nitrobenzene containing dissolved HC1, the reverse reaction, i.e. addition of HC1, takes place. The fact that this may be interpreted as a retardation of the degradation process may have contributed to the confusion which has arisen and emphasizes the care which must be taken to disentangle the possible catalytic effect of HC1 when concurrent addition of HC1 to the polyenes is possible. 

The polyester domains of suberized walls can also be depolymerized using chemical and/or enzymatic approaches similar to those used for cutin. The aromatic domains are far more difficult to depolymerize as C-C and C-O-C crosslinks are probably present in such domains. Therefore, more drastic degradation procedures such as nitrobenzene, CuO oxidation, or thioglycolic... 

The effect of chain length on the ability of degraded amylose to form complexes was studied by Whistler and associates.63 When amylose is hydrolyzed to a degree of polymerization of 20 to 40, it no longer forms insoluble complexes with nitrobenzene, n-pentyl acetate and 2-heptanone, although it still does with 1-butanol and 2-nitropropane. 

Consequently, the native and enzymatically liberated lignins from white Scots pine, oak, birch, maple, kiri1 wood and bagasse were oxidized with nitrobenzene in alkali. The method of Stone 113) was applied quantitatively in this study. The amount of each degradation product obtained from each of the lignins is listed in Table 12 110). 

Apart from nitrobenzene, trichlorobenzene in particular was the preferred solvent up until a few years ago. It has now been replaced by other solvents such as high-boiling hydrocarbons (kerosene, naphthalene) and also alcohols and glycols, because traces of polychlorinated biphenyls may be formed. These are not easily degradable. With hydrocarbons, however, the possibility of fire and explosion must be considered in designing suitable production units. 

Soil A reversible equilibrium is quickly established when aniline covalently bonds with humates in soils forming imine linkages. These quinoidal structures may oxidize to give nitrogen-substituted quinoid rings. The average second-order rate constant for this reaction in a pH 7 buffer at 30 °C is 9.47 x 10 L/g-h (Parris, 1980). In sterile soil, aniline partially degraded to azobenzene, phenazine, formanilide, and acetanilide and the tentatively identified compounds nitrobenzene and jD-benzoquinone (Pillai et ah, 1982). 

Biological In an in vitro study, the soil fungi Fusarium oxysponim and Paecilomyces varioti degraded pendimethalin to W(l-ethylpropyl)-3,4-dimethyl-2-nitrobenzene-l,6-diamine and 3,4-di-methyl-2,6-dinitroaniline. The latter compound was the only metabolite identified by another soil fungus namely, Rhizoctonia bataticola (Singh and Kulshrestha, 1991). 

Lipcz3mska-Kochany, E. Degradation of aqueous nitrophenols and nitrobenzene by means of the Fenton reaction, Chemosphere, 22(5/6) 529-536, 1991. 

Finally, a few miscellaneous compounds which were identified in the Delaware River and which have not been previously reported as water contaminants will be discussed Chloro (trifluoromethyl) aniline and chloro (trifluoromethyl) nitrobenzene (no. 55 and 56) were identified in the water, they had maximum concentrations at river mile 78. Both compounds represent common sub-structures in various pesticide and dye molecules, and several of the companies located along the river have patents using these compounds (30-32j. It is possible that these compounds are actually present in the river water as such, but it is also possible that they are formed in the GC injection port by pyrolytic degradation of larger pesticide or dye molecules (see above). All three binaphthyl-sulfone isomers (no. 92) were identified in the river water near Philadelphia. Product literature for one of the companies in the area indicates production of condensed sulfonated polymers derived from naphthalene sulfonic acid and maleic anhydride. It seems likely that the binaphthylsulfones are formed as by-products during preparation of this commercial product. 

Exposure. Exposure to 1,3-DNB is currently measured indirectly by determining levels of methemoglobin in the blood (Donovan 1990). However, increased methemoglobin formation is not a specific response to 1,3-DNB exposure and may occur after exposure to other nitrobenzene compounds such as the other two isomers of dinitrobenzene. Determination of methemoglobin levels is widely used and is a reliable detection method. Very few methods are available for direct evaluation of 1,3-DNB levels, and they are not extensively used, probably because of the relatively rapid rate of conversion of 1,3-DNB to its degradation products (Cossum and Rickert 1985). Preliminary data suggested that the formation of adducts of 1,3,5-TNB with tissue DNA and/or with blood proteins may be useful as markers for exposure to 1,3,5-TNB (Reddy et al. 1991). Further research with both 1,3-DNB and 1,3,5-TNB in the area of adduct formation could provide valuable additional information. 

Gomolka E, Gomolka B. 1979. Ability of activated sludge to degrade nitrobenzene in municipal wastewater. Acta Hydrochim Flydrobiol 79 605-622. 

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