Diamino-nitrotoluenes

Figure 14.6 Reduction pathway of 2,4,6-trinitrotoluene to aminodi-nitrotoluenes (ADNTs), diamino-nitrotoluenes (DANTs), and tri-aminotoluene (TAT).

TNT Amino-dinitrotoluenes Diamino-nitrotoluenes Hydroxylamino-dinitrotoluenes Tetranitro-azoxynitrotoluenes (High organic) Aerobic... 

Successive reduction of TNT to aminodinitrotoluenes (ADNTs) and diamino-nitrotoluenes (DANTs) leads to a sequential decrease of toxicity to the microalga, Pseudokirchneriella subcapitata (formerly Selenastrum capricornutum) [32] and in the Microtox test [30], Further toxicity decrease occurs in the latter with an additional reduction to triaminotoluene (TAT) [30] (Table 4.2 and Table 4.3). The ADNTs were also less toxic than the parent compound to the freshwater fish Pimephales promelas [19], and embryos of the frog Xenopus laevis [33], The reduction of 2,3,6-TNT to ADNTs promoted decreased toxicity in studies with P. promelas and D. magna... 

Dichlorobenzene, aminotoluene, nitrotoluene isomers, diamino-toluene, and dinitrotoluene isomers... 

Haidour and Ramos (1996) analyzed the degradation products of 2,4,6-trinitrotoluene, 2,4-dinitrotoluene, and 2,6-dinitrotoluene by the bacterium Pseudomonas sp. clone A under aerobic conditions. Reduced 2,4,6-trinitrotoluene metabolites, which were not used as a nitrogen source by this bacterium, were 2-hydroxyamino-4,6-dinitrotoluene, 4-hydroxyamino-2,6-dinitrotoluene, and 2,4-diamino-6-nitrotoluene. 

C. bifermentam strain CYS-1 was also isolated from our anaerobic bioreactor. Shin Crawford (1995) examined the ability of CYS-1 to degrade TNT cometabolically in various defined media. This strain could overcome the toxicity of and degrade >150 ppm TNT in liquid media supplemented with a rich cosubstrate such as yeast extract or trypticase soy, given an appropriate inoculum ( 107 CFU/ml). Furthermore, it was found that CYS-1 could degrade TNT which contaminated a sandy loam soil. The degradation of TNT proceeded through the transient intermediates 4-amino-2,6-dinitrotoluene and 2,4-diamino-6-nitrotoluene. 

The 4-hydroxylamino compd can be extracted from the reaction mixt. This procedure has also been used by others (Refs 2,67 69). A report that the 2-hydroxylamino compd could be made by reducing TNT (Ref 4) could not be duplicated (Refs 67 69). Reduction of TNT with ethanolic ammonium sulfide gives a good yield of 2,4-diamino-6-nitrotoluene (Refs 9 67)... 

In addition to the compds in Table 1, they obtained evidence for 2-hydroxylamino4,6-dinitro-toluene, 2,4-diamino-6-nitrotoluene, 2,6-diamino-4-nitrotoluene, 2,4,6-trinitrobenzoic acid and (with considerable lack of confidence) 2,4,6-tri-nitrobenzyl alcohol. They confirmed that 2,2 6,6,-tetranitro4,4f azoxytoluene is not a constituent of fresh urine, but may form from 4-hydroxylamino-2,6-dinitrotoluene when the urine is allowed to stand or during isolation procedures. They saw almost no unmetabolized TNT in urine. The urine of orally dosed rats and mice had a bright red color, but not that of dogs and rabbits. The radioactivity of labeled TNT was mainly excreted, but some ended up distributed in various organs... 

Diamino-4-ni trotoluene 2-Ethoxy-4-nitrotoluene, small amount 39... 

TNT is readily absorbed through skin, especially when skin is moist. It is excreted in urine more than in feces some is found in bile. The major biotransformation reaction is nitroreduction and, to a lesser extent, oxidation. The main metabolite formed by nitroreduction seems to be 4-amino-2,6-dinitrotoluene (4-ADNT). Other metabolites include 2-amino-4,6-dinitrotoluene (2-ADNT), 2,4-diamino-6-nitrotoluene, and 2,6-diamino-4-nitrotoluene. The metabolites are excreted in the urine as glucuronide conjugates and in the free form. Ring oxidation products of TNT such as trinitrobenzylalcohol, trinitrobenzoic acid, and simultaneous oxidation and reduction metabolites such as 2,6-dinitro-4-amino-benzylalcohol and 2,6-dinitro-4-amino-m-cresol are of less importance. Untransformed TNT is also excreted in the urine. ADNT and TNT concentrations were found in workers in explosives factories. 4-ADNT excretion was reported to be complete within 3M days after exposure. However, another study reported detectable urine concentration of ADNT in explosives workers even after 17 days away from the workplace. 

Various modern products may serve as sources for trace amounts of PAA. The origins, known hazards, release restrictions and environmental fate of PAA derived from azo dyes have been reviewed2. The metabolism of nitroarenes is closely linked to that of aromatic amines, as shown in a simplified way in equation 369. Gloeophyllum trabeum cultures spiked with TNT show formation of nitroaromatic amines such as 2-ami no-4,6-dinitrotoluene, 4-amino-2,6-dinitrotoluene and 2,4-diamino-6-nitrotoluene. Also, autoxi-dation of the methyl group of TNT or its metabolites may take part in the degradation process, as shown by the presence of Schiff bases and oligomeric and polymeric species detection and determination of the analytes after LLE and concentration were by HPLC-UVD or GC-MS70. 

In an ironic aside, it is noted that the most recently suggested new use for phosgene is to "make safe" thousands of tons of TNT (2,4,6-trinitrotoluene) from redundant weapons, no longer required now that the Cold War has ended. Treatment of the TNT with ammonium sulfide would reduce it to 2,4-diamino-6-nitrotoluene, which could then be treated with phosgene to give 2,4-diisocyanato-6-nitrotoluene (NDTI), a potentially valuable precursor for polyurethane manufacture [64d]. Thus, instead of potentially hazardous, and certainly wasteful, destruction of the TNT, the use of phosgene could convert it into a valuable industrial commodity. 

Gilcrease, P.C. and V.G. Murphy. 1995. Bioconversion of 2,4-diamino-6-nitrotoluene to a novel metabolite under anoxic and aerobic conditions. Appl. Environ. Microbiol. 61 4209-4214. 

Dawel G et al., Structure of a laccase-mediated product of coupling of 2,4-diamino-6-nitrotoluene (2,4-DANT) to guaiacol, a model for coupling of 2,4,6-trinitrotoluene (TNT) metabolites to humic organic soil matrix, Appl. Environ. Microbiol., 63, 2560, 1997. 

Karamova NS et al., Compounds 2,4,6-trinitrotoluene and 2,4-diamino-6-nitrotoluene The absence of recA-dependent mutagenesis, Russ. J. Genet., 31, 528, 1995. 

Reduction of the nitro group that resides para to the methyl group (at the 4 position) is thermodynamically preferable to reduction of those at the 2 and 6 positions, as predicted by the work of McCormick et al. [19]. It is known that the 4-amino reduction product is the predominant reduced form of TNT in aerobic environments, and 2,4-diamino-6-nitrotoluene predominates under mildly acidic (pH 6) anaerobic conditions [33], It also has been reported that 2,4-diamino-6-nitrotoluene (2,4-DANT) can be generated under aerobic conditions by reaction with certain minerals associated with clays, and is stable in the surface soil environment [34],... 

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