3 : 5-Dinitroaniline

In a 1-1. round-bottomed flask fitted with a mechanical stirrer are placed SO ml. (55.4 g., 0.49 mole) of chlorobenzene (Note 1), 300 ml. of concentrated sulfuric acid (sp. gr., 1.84), and 50 ml. (92 g.) of fuming sulfuric acid (containing approximately 25% 

Without further drying, the potassium 4-chloro-3,5-dinitro-benzenesulfonate is recrystallized from 600 ml. of boiling water (Note 3). Insoluble material is removed by decantation and filtration of the hot solution. The solution is cooled to 5-10° for 12 hours, and the crystalline potassium salt is collected on a suction filter, pressed as dry as possible, and placed at once in a solution of 400 ml. of concentrated ammonium hydroxide (sp. gr. 0.90) in 400 ml. of water. The solution is boiled for 1 hour under a reflux condenser which has been connected to a gas absorption trap,2 and then is cooled at 5-10° for 12 hours. The orange, crystalline potassium 4-amino-3,5-dinitrobenzenesulfo-nate is filtered with suction and pressed as dry as possible on a 10-cm. Buchner funnel. 

The damp salt is placed in a solution of 200 ml. of concentrated sulfuric acid (sp. gr. 1.84) and 200 ml. of water in a 1-1. round-bottomed flask, and the mixture is boiled vigorously under reflux for 6 hours (Note 4). The hot acid solution is poured onto 1 kg. of cracked ice, filtered on a 7.5-cm. Buchner funnel, slurried twice with 100-ml. portions of water, and pressed as dry as possible on the funnel. The damp, impure 2,6-dinitroaniline is dissolved in 500 ml. of hot 95% ethanol, and the solution is boiled under reflux for 10 minutes with 3 g. of Norit and 3 g. of filter aid. The hot ethanol solution is filtered through a heated funnel (Note 5) and cooled slowly to room temperature. Light-orange 

The best grade of Eastman Kodak Company chlorobenzene was used. 

Since the reaction is moderately exothermic during the first 4 hours, the temperature of the reaction mixture must be controlled carefully. A gas trap2 may be used to absorb the small amount of nitrogen dioxide evolved, or the reaction may be carried out in a hood. Excessive fuming is avoided if the temperature is kept in the range 110-115°. 

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Dinitroaniline. This preparation is another illustration of the mobile character of the chlorine atom in 2 4-dinitro-l-chlorobenzene ... 

The operation of the nitronium ion in these media was later proved conclusively. "- The rates of nitration of 2-phenylethanesulphonate anion ([Aromatic] < c. 0-5 mol l i), toluene-(U-sulphonate anion, p-nitrophenol, A(-methyl-2,4-dinitroaniline and A(-methyl-iV,2,4-trinitro-aniline in aqueous solutions of nitric acid depend on the first power of the concentration of the aromatic. The dependence on acidity of the rate of 0-exchange between nitric acid and water was measured, " and formal first-order rate constants for oxygen exchange were defined by dividing the rates of exchange by the concentration of water. Comparison of these constants with the corresponding results for the reactions of the aromatic compounds yielded the scale of relative reactivities sho-wn in table 2.1. 

Thermal—Oxidative-Resistance Coatings. The thermal stabihty of coatings produced by either covalendy or noncovalendy incorporating 2,4-dinitroaniline into an inorganic siUcate network and coating it onto a sapphire substrate has been examined (67). Although some increase in the thermal... 

Pigment Orange 5 [3468-63-1] 12075 monoa2o (Dinitraniline Orange) coupling of dia2oti2ed 2,4-dinitroaniline with 2-naphthol... 

Blues are the single most important color in the disperse class, both in terms of amounts produced and doUar sales volume. Among all dyes. Disperse Blue 79 (100) (6-bromo-2,4-dinitroaniline [1817-73-8] coupled to 3-bis-(2-acetoxyethyl)-amino-/)-acetophenetidine [20249-05-2]) was the highest volume dye in the late 1980s and continues. As reported in 1985, the United States produced 2872 tons valued at 7.7 million. 

Odier bromine-containing dye intemiediates include 6-bromo-2,4-dinitroaniline [1817-73-8] C H BrN O, and 5,7-dibromoisatin [6374-91-0] CgH2Bi2N02. Bromodinitroaniline is used in making a2o dyes and dibromoisatin is used in making Alizarin Indigos B, 3R, and G. 

Dinitroaniline [97-02-9] M 183.1, m 180 , 8349 12,300 in dil aq HCIO4, pK -4.27 (aq H2SO4). Crystd from boiling EtOH by adding one-third volume of water and cooling slowly. Dried in a steam oven. 

R-(-)-Phenylglycinol (5 g, 36.5 mmol) was added to a solution of Zincke salt 115 (10.3 g, 33.3 mmol) in n-butanol (100 mL) at 20 °C. The resulting deep red solution was refluxed during 20 h. Removal of the solvent under reduced pressure left a residue that was treated with HpO (70 mL). The precipitate (2,4-dinitroaniline hydrochloride) was eliminated by filtration, and the operation was repeated twice. The combined aqueous phase was basified with concentrated ammonia (5 mL) and washed twice with EtOAc (200 mL) in order to remove the remaining 2,4-dinitroaniline and the excess of R- )-phenylglycinol. Evaporation of water gave salt 122 (7.53 g, 86%) as a pale orange gum. 

Formation of diamines from dinitro compounds, which are unable to interact intramolecularly, presents no problem. Very large volumes of diaminotoluene, a precursor to toluene diisocyanate, are produced by hydrogenation of dinitrotoluene over either nickel or palladium-on-carbon. Selective hydrogenation of one or the other of two nitro groups is much more of a challenge, but a number of outstanding successes have been recorded. A case in point is the hydrogenation of 2,4-dinitroaniline (11) to 4-nitro-l,2-benzenediamine (12) (2) or to 2-nitro-l,4-benzenediamine (10). 

AG° was calculated for eleven amines, ranging from 2,4-dinitroaniline (AG° = + 50 kJ mol-1) to aniline ( — 41), 4-morpholinoaniline ( — 99), and 4-dimethyl-aminoaniline ( — 108). The results demonstrate clearly that a primary electron transfer is very likely, at least for those aniline derivatives with a strong electron donor in the 4-position. 

N-allyl-2,4-dinitroaniline, catalysis of nucleophilic substitution by, 422 N-allyl-l-naphthylamine,rearrangement of,473 allyl phenyl thioether, rearrangement of, 473, 474... 

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