Polynitro Aromatics

A number of environmentally significant nitroaromatics, such as the dinitro herbicides, nitroaromatic munitions, and textile dye intermediates, contain two or more 

There has been considerable interest in the reductive transformation of the polynitroaromatics, 2,4-dinitrotoluene (2,4-DNT), and 2,4,6-trinitrotoluene (TNT) in anaerobic environments. These chemicals are high volume munitions, which because of their improper disposal and storage, have contaminated soils and aquifers at numerous sites (Kaplan and Kaplan, 1982). Enhancing the reduction of these contaminants in situ using abiotic and biotic processes has been proposed as a remediation technique for contaminated soils and sediments (Kaplan, 1990 Ou et al., 1992). The reduction of TNT and DNT, as well as other polynitroaromatics, has been studied in some detail in anaerobic microbial enzyme systems (McCormick et al., 

DNT was also observed in the enzyme system. The reduction of 2,4-DNT was very selective reduction of the 2-nitro group did not take place until reduction of the 4-nitro group was complete. 

In contrast, reduction of 2,4-dinitroaniline (X = NH2) and 2,4-dinitrophenol (X = OH) was selective for the nitro groups in the 2-position. 

Furthermore, reduction of the second nitro group occurred at a much slower rate than that of the first nitro group. 

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As well as the cr-complexes discussed above, aromatic molecules combine with such compounds as quinones, polynitro-aromatics and tetra-cyanoethylene to give more loosely bound structures called charge-transfer complexes. Closely related to these, but usually known as Tt-complexes, are the associations formed by aromatic compounds and halogens, hydrogen halides, silver ions and other electrophiles. 

Aliphatic amines are simple lone-pair n-donors, similarly to other n-donors like phosphines, ethers, alcohols, iodides etc. Aromatic amines may be both n- and rr-donors132. Typical rr-donors are polycyclic aromatic derivatives 7r-acceptors are polynitro aromatic derivatives, quinones etc. 

Examples of such charge-transfer complexes include the complex formed between a metal ion and a -n orbital of a double bond or an aromatic system , the complex formed between polynitro aromatics (such as picric acid) and other w-orbital-containing molecules, and complexes of I2 and Br2 with amines, ketones, aromatics, etc ° Phenols and quinones also form charge-transfer complexes ... 

Addn Compds of Ethylenediperchlorate with acid polynitro aromatic compds)... 

Sauer (Ref 9) stabilized Dinitrodiaminomethane at a temp below its mp by coating with 0.1 to 2.0% polynitrophenol or polynitro aromatic carboxylic acid by means of absorption, recrystn or evapn from a non solvent. Thus, 98% of the pure compd 8C 2% Picric Acid were mixed 8t benz added to form a slurry. After the mixt was dried under vacuum, tests at 75° showed improved stabi-... 

Thermal polymerization of VCZ is initiated by nitroalkanes (31), tetranitromethane (32) and polynitro aromatic compounds (28). 

Vanadium salts have also been found to be effective as catalysts in various electrolytic oxidation and reduction processes for example in the preparation of hypochlorites,12 the reduction of polynitro-aromatic compounds,13 and in the sulphonation of aromatic compounds.14 On... 

There exists a large group of cryst complexes contg in stoichiometric proportions polynitro -aromatic substs, such as TNB or PA, and aromatic hydrocarbons and bases and their derivs. These complexes are, for the most part, unstable, and some of them are expl. Some examples of these are the following ... 

Trinitrobenzene is only moderately soluble in hot alcohol, more readily in acetone, ether, and benzene. Like other polynitro aromatic compounds it forms colored molecular compounds with many aromatic hydrocarbons and organic bases.8 The compound... 

Like most polynitro-aromatics, picramide forms addition compounds with condensed ring aromatic hydrocarbons. Compounds containing their constituents in 1 1 molecular proportion include those with ... 

Tetranitromethane like polynitro-aromatic hydrocarbons is able to form addition compounds (p. 222, Fig. 47). Nevertheless, the existence of an addition compound of tetranitromethane with benzene has not been proved by thermal analysis, when this was carried out recently by T. Urbanski, Piskorz, Centner and Maciejewski [59], They also examined a number of other systems by means of thermal analysis. The compositions of various eutectics determined by the above authors are shown in Table 127. 

The specific features of meta-cyclization of aza-aromatic compounds with bifunctional nucleophilic reagents were formulated by Strauss in a number of papers on the reactions of polynitro aromatics and their aza-analogues with enamines, CH-active acetamidines, and other 1,3-dinucleophiles (74ACR181). 

X Ray analysis of aliphatic, nitrocom pounds nitrate esters, nitramincs and polynitro aromatic addition compounds 88... 

Addn Compds of Ethylenediperchlorate with acid polynitro aromatic compds) 5) ADL PureExplCompds, Part 1(1947), 69... 

With pyridine iV-imine, 2,4-dinitrofluorobenzene gives pyridine IV-2,4-dinitrophenylimine.70 71 Other polynitro aromatics react analogously. Since it is not possible to isolate the pyridine iV-imine it is prepared in situ from iV-aminopyridinium salts and sodium ethoxide [Eq. (6)]. 

Other complex metal hydrides can only rarely be applied to reduction of C=C bonds. Sodium borohydride, which can be used in aqueous-alcoholic solution, seems not normally to attack ethylenic bonds. A few cases only of partial reduction of cyclic iminum salts96 and of selective reduction of unusually activated ethylenic bonds97 have been reported. However, some polynitro aromatic compounds, e.g., 1,3,5-trinitrobenzene, can be converted in high yield with saturation of the aromatic system into nitrocyclohexanes or nitro-cyclohexenes.98 Sodium hydridotrimethoxyborate has proved valuable as a mild reducing agent for preparation of a series of nitroparaffins from nitro-alkenes."... 

Further use of this oxidant to produce a number of polynitro aromatics was reported by Nielsen and co-workers [71 ] in their remarkable paper. The authors also reviewed work on the other oxidants used to pass from HN2 to NOj Caro acid, peracetic, permaleic, m-chloroperbenzoic and perbenzoic acids. They pointed out that the power of the oxidant is proportional to the acid strength of deoxy peracid. Peracetic and m-chloroperbenzoic acids are suitable for the oxidation of aliphatic primary amines, whereas peracetic, peroxytrifluoroacetic and peroxymaleic acids are best for the oxidation of ring substituted anilines. Potassium persulphate in sulphuric acid was also used successfully (71 ]. 

Organic nitro compounds Nitroalkyls polynitro-aromatic or alkyl Nitromethane tetianitromethtine ... 

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