Dinitrobenzene from nitrobenzene

Catalytic hydtogenation is the most efficient method for the large scale manufacture of many aromatic and ahphatic amines. Some of the commercially important amines produced by catalytic hydrogenation include aniline (from nitrobenzene), 1,6-hexanediamine (from adiponitrile), isophoronediamine (from 3-nitro-l,5,5-trimethylcyclohexanecarbonitrile), phenylenediamine (from dinitrobenzene), toluenediamine (from dinitrotoluene), toluidine (from nitrotoluene), and xyhdine (from nitroxylene). As these examples suggest, aromatic amines ate usually made by hydrogenating the... 

Production volume figures for 1,3-DNB are not easily available because it is produced as a mixture with other nitrobenzene isomers during the manufacturing process. In the United States, DuPont alone reportedly generated 70,000-72,000 pounds of 1,3-DNB annually from production of dinitrobenzene and nitrobenzene (EPA 1991b). The production volumes for 1,3-DNB by other manufacturers are not known. Production data for 1,3,5-TNB by producers in the United States are unknown. 

Ogata and Tsuchida [76] found in 1956 that the orienting activity of the nitro group may be partly changed in the presence of mercury ions. Thus, from nitrobenzene fairly considerable quantities of o- dinitrobenzene are obtained Blong with... 

Method A. Note This method yieids 1,3-dinitrobenzene from benzene or nitrobenzene and the 4-nitro derivative from chioro- or bromobenzene, benzyi chioride, or toiuene dinitro derivatives are obtained from phenoi, acetaniiide, naphthaiene, and biphenyi. 

Comments This procedure will yield /n-dinitrobenzene from either benzene or nitrobenzene, the p-nitro derivatives from chlorobenzene, bromo-benzene, benzyl chloride, etc. Toluene yields an oily mixture of 0- and p-nitro compounds and should be subjected to procedure (b). 

The acids are mixed in a flask (500 c.c.), and the nitrobenzene added in portions of 5—10 c.c. at a time. Heat is evolved, and the mass becomes somewhat deeper in colour. When the nitrobenzene has been added, the flask is heated for a shoit time on the water-bath. K few drops are then potiied into a test-tube of water. The dinitrobenzene should, if the reaction is complete, separate out as a hard pale yellow cake If it is semi-sohd, the heating" must be continued. The contents of the flask are then poured, whilst warm, into a large quantity of water. The dinitrobenzene, which separates out, is filteied at the punap and well washed with water. It is then dried. The yield is nearly theoretical. A few grams should be recrystallised from spirit. The remainder may be used for the next preparation without further puiification. 

OS 31] ]R 4] ]P 23] Under electroosmotic flow conditions, the reactant benzene was mobilized as a microemulsion using sodium dodecyl sulfate (SDS) as surfactant [103] (see also [14]). The nitronium ions, generated in situ from sulfuric and nitric acid, were moved by electrophoretic forces. By this means, a 65% yield of a nitrobenzene was obtained consecutive nitration products such as 1,3-dinitrobenzene (8% yield) and 1,3,5-trinitrobenzene (5% yield) were also produced. 

To a mixture of 14 c.c. (25 g.) of concentrated sulphuric acid and 10 c.c. (15 g.) of fuming nitric acid in an open flask 10 g. of nitrobenzene are gradually added (fume chamber). The mixture is then heated on the water bath for half an hour with frequent shaking. The reaction mixture is cooled somewhat and then poured with stirring into cold water. The dinitrobenzene solidifies, is filtered with suction, washed with water, pressed on porous plate, and crystallised from alcohol. Melting point 90°. Yield 10-12 g. 

The apparent relationship between torsion angle and 170 chemical shift has been explored further by examination of the data for several ortho alkyl-substituted nitrobenzenes and dinitrobenzenes (Table 23). The deshielding values of the shifts reflect increasing nitrogen-oxygen double bond character, which is expected as the nitro group is rotated from the plane of the aromatic ring. 

Fig. 3 Electrochemical and homogeneous standard free energies of activation for self-exchange in the reduction of aromatic hydrocarbons in iV.A -dimethylformamide as a function of their equivalent hard sphere radius, a. 1, Benzonitrile 2, 4-cyanopyridine 3, o-toluonitrile 4, w-toluonitrile 5, p-toluonitrile 6, phthalonitrile 7, terephthalonitrile 8, nitrobenzene 9, w-dinitrobenzene 10, p-dinitrobenzene 11, w-nitrobenzonitrile 12, dibenzofuran 13, dibenzothiophene 14, p-naphthoquinone 15, anthracene 16, perylene 17, naphthalene 18, tra 5-stilbene. Solid lines denote theoretical predictions. (Adapted from Kojima and Bard, 1975.)...

The yields of reaction products from thermal nucleophilic substitution reactions in DMSO of 0- and p-nitrohalobenzenes (Zhang et al. 1993) or p-dinitrobenzene (Liu et al. 2002) with the sodium salt of ethyl a-cyanoacetate were found to be markedly diminished from the addition of small amounts of strong electron acceptors such as nitrobenzenes. At the same time, little or no diminution effects on the yields of the reaction products were observed from the addition of radical traps such as nitroxyls. These results are consistent with the conclusion that such reactions proceed via a nonchain radical nucleophilic substitution mechanism (Scheme 4.26). 

Nitric acid in the presence of catalytic amounts of mercury (II) nitrate reacts with some substrates, under certain conditions, to give substimted polynitrophenols. The first example, reported by Boeters and Wolffenstein and known as oxynitration , involved treating benzene with 50-55 % nitric acid in the presence of mercury (II) nitrate. The product is a mixture of unreacted benzene, nitrobenzene, m-dinitrobenzene, 2,4-dinitrophenol and picric acid, from which the latter can be isolated by steam distillation of this crude mixture followed by recrystallization of the residue from hot water. 

The dipole moment is a property of the molecule that results from charge separations like those discussed above. However, it is not possible to measure the dipole moment of an individual bond within a molecule we can measure only the total moment of the molecule, which is the vectorial sum of the individual bond moments.32 These individual moments are roughly the same from molecule to molecule,33 but this constancy is by no means universal. Thus, from the dipole moments of toluene and nitrobenzene (Figure 1.10)34 we should expect the moment of p-nitrotoluene to be about 4.36 D. The actual value 4.39 D is reasonable. However, the moment of p-cresol (1.57 D) is quite far from the predicted value of 1.11 D. In some cases, molecules may have substantial individual bond moments but no total moments at all because the individual moments are canceled out by the overall symmetry of the molecule. Some examples are CC14, tr[Pg.16]

Trinitrodipheny Isulfone, crysts (from glac acet ac), mp 196—97° was prepd by heating 4-chloro-rl,3-dinitrobenzene or 2,4-dinitrophenyl-p-toluenesulfonate with Na 3-nitrobenzene-l-sulfinate in aq ale (Refs 1 St 3) 3,5,4 TrinitrodiphenyIsulfone, ndls, mp 199° prepd by heating 3 nitrophenyI-(4-nitrophenyl)-sulfone with a mixt of fuming nitric acid 8c sulfuric acid at 150°(Refs 2St4)... 

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