2.4- Dichloro-l-nitrobenzene

Dichloro-l-nitrobenzene [99-54-7] M 192.0, m 43°. Crystd from absolute EtOH. 

The replacement of a nuclear substituent such as hydroxyl (-OH), chloro, (-C1), or sulfonic acid (-S03H) with amino (-NH2) by the use of ammonia (ammonolysis) has been practiced for some time with feedstocks that have reaction-inducing groups present thereby making replacement easier. For example, l,4-dichloro-2-nitrobenzene can be changed readily to 4-chloro-2-nitroaniline by treatment with aqueous ammonia. Other molecules offer more processing difficulty, and pressure vessels are required for the production of aniline from chlorobenzene or from phenol (Fig. 3). 

The 2004 report on the risk assessment noted that approximately 22,950 tonnes of 1,4-DCB were used per year in the European Union in 1985 20,500 tonnes in 1987 and 16,400 tonnes in 1991. This substance had four primary uses 49.3% of the total was used as a chemical intermediate (e.g., in making l,4-dichloro-2-nitrobenzene, a precursor for dyes and pigments) 21.9% in toilet blocks/air fresheners 28.1% in moth repellants and 0.7% as a processing aid in the production of grinding wheels [116, p. vii]. 

Manufacturers in the European Union have utilized 1,4-DCB for many of the same purposes as users in the United States. Of the 14,494 toimes per year consumed circa 1994, 49% was used as an intermediate, 22% toilet blocks/ air fresheners, 28% moth repellents, and 0.7% grinding wheels. The intermediate use was primarily in the production of l,4-dichloro-2-nitrobenzene, a precursor for dyes and pigments [57]. Consumer uses declined after 1994 as shown in Figure 4.3 [65]. Most of the mass produced in the European Union was exported for use in polymer production some of the polymer was then reimported to the European Union [65]. 

The nitration of l,3,5-trichloro-2-nitrobenzene (8) to l,3,5-trichloro-2,4-dinitrobenzene (9) with dinitrogen pentoxide in absolute nitric acid goes to completion in only 2-4 minutes at 32-35 °C. Further nitration of (9) would yield l,3,5-trichloro-2,4,6-trinitrobenzene (10) which undergoes ammonolysis on treatment with ammonia in toluene to give the thermally stable explosive 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) (11). The same sequence of reactions with l,3-dichloro-2-nitrobenzene provides a route to l,3-diamino-2,4,6-trinitrobenzene (DATE). Such reactions are clean and occur in essentially quantitative yield. 

DichlorO 3-oxo-3,4-dihydroquinoxaIine-2-carboxylic acid undergoes decarboxylation upon heating in nitrobenzene at reflux temperature to yield 6,7-dichloroquinoxalin-2(l//)-... 

Nonanitroterphenyl (NONA) [Structure (2.38)] is produced by the condensation of 2 moles of picryl chloride with l,3-dichloro-2,4,6-trinitroben-zene (styphnyl chloride)in the presence of copper dust at 210°C using nitrobenzene as a medium (Ullmann s Condensation) [90]. It has a density of 1.78 g cm and exceptional heat stability, melting at 440-450 °C with decomposition which together with a low volume of split-off gases render it as an interesting explosive for booster explosives in space technology [91]. 

V in both methanol and acetonitrile. These values, combined with the doping density and the band gap of 1.12 eV for p-Si places the conduction band edge in methanol and acetonitrile at -0.85V (vs SCE). The supraband edqe redox couples chosen for the two electrolytes were 1,3 dimethoxy-4-nitrobenzene (8,=-l -0V vs SCE)for methanol, and 1 nitronaphthalene (E0=-l. 08), 1, 2 dichloro 4-nitrobenzene (E0= -0.95), and anthraquinone (Eo=-0.95) for acetonitrile. These redox couples lie from 0.IV to 0.24V above the conduction band edge of p-Si, and hence, in the conventional model, could not be photoreduced by p-Si. 

Identify the product from each of the following reactions (a) l-chloro-4-nitrobenzene + sodium methoxide (b) l,2-dichloro-4-nitrobenzene + 1 mole of sodium methoxide (c) 4-(2-chlorophenyl)-butanonitriie + sodium amide (d) 3-bromo-4 methylbiphenyl + potassium amide,... 

Fig. 2. Metabolism of model substrates by GST. The following reactions are catalyzed by GST (a) f-chloro-2,4-dinitrobenzene, (b) l,2-dichloro-4-nitrobenzene, (c)r/-a>w-4-phenyl-3-buten-2-one, (d) ethacrynic acid, (e) l,2-epoxy-3-(p-nitrophenoxy)propane, and (f) menaphthyl sulfate.

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