Nitronaphthalenes

Colourless crystals m.p. 50 C, b.p. 301 C. Basic and forms sparingly soluble salts with mineral acids. Prepared by the reduction of 1-nitronaphthalene with iron and a trace of hydrochloric acid or by the action of ammonia upon l-naphlhol at a high temperature and pressure. 

In the nitration of benzene, wj-dinilro- and sym-trinitrobenzenes are obtained under more vigorous conditions. With naphthalene, 1-nitronaphthalene is the first product and further nitration gives a mixture of 1,5- and 1,8-dinitronaphthalenes 2-nitronaphthalene is never obtained. 

In the naphthalene series, a-naphthylamine is easily obtained by the reduction of the readily accessible a-nitronaphthalene ... 

Davies and Warren" found that when 1,4-dimethylnaphthalene was treated with nitric acid in acetic anhydride, and the mixture was quenched after 34 hr, a pale yellow solid with an ultraviolet spectrum similar to that of a-nitro-naphthalene was produced. However, if the mixture was allowed to stand for 5 days, the product was i-methyl-4 nitromethylnaphthalene, in agreement with earlier findings. Davies and Warren suggested that the intermediate was 1,4-dimethyl-5 nitronaphthalene, which underwent acid catalysed rearrangement to the final product. Robinson pointed out that this is improbable, and suggested an alternative structure (iv) for the intermediate, together with a scheme for its formation from an adduct (ill) (analogous to l above) and its subsequent decomposition to the observed product. 

Thompson has recently obtained clear evidence, from n.m.r. studies of the reaction mixture, that the observed product (vl) is not produced via 1,4-dimethyl-5-nitronaphthalene. 

Nitration. Naphthalene is easily nitrated with mixed acids, eg, nitric and sulfuric, at moderate temperatures to give mostly 1-nitronaphthalene and small quantities, 3—5%, of 2-nitronaphthalene. 2-Nitronaphthalene [581-89-5] is not made in substantial amounts by direct nitration and must be produced by indirect methods, eg, the Bucherer reaction starting with 2-naphthalenol (2-naphthol [135-19-3]). However, the 2-naphthylamine [91-59-8] made using this route is a carcinogen thus the Bucherer method is seldom used in the United States. 

Nitronaphthalene. 1-Nitronaphthalene is manufactured by nitrating naphthalene with nitric and sulfuric acids at ca 40—50°C (37). The product is obtained in very high yield and contains ca 3—10 wt % 2-nitronaphthalene and traces of dinitronaphthalene the product can be purified by distillation or by recrystaUization from alcohol. 1-Nitronaphthalene is important for the manufacture of 1-naphthalenearnine. Photochemical nitration of naphthalene by tetranitromethane in dichioromethane and acetonitrile to give 1-nitronaphthalene has been described (38). 

Nitronaphthalene is metabolized to the carcinogenic 2-naphthylarnine in the human body (39). Respirators, protective clothing, proper engineering controls, and medical monitoring programs for workers involved in making by-product 2-nitronaphthalene should be used. 

Nitronaphthalenesulfonic Acids. Nitronaphthalenesulfonic acids can be obtained either by the sulfonation of 1-nitronaphthalene or by the nitration of 1- or 2-naphthalenesulfonic acid. Thus the sulfonation of 1-nitronaphthalene with oleum at ca 25°C gives mainly 5-nitro-l-naphthalenesulfonic acid/77521-00-5]. The mononitration of 1-naphthalenesulfonic acid gives mainly 5- and 8-nitro-l-naphthalenesulfonic acid/717-41-9] and mononitration of 2-naphthalenesulfonic acid gives mainly 5-nitro-2-naphthalenesulfonic acid [86-69-1] and 8-nitro-2-naphthalenesulfonic acid [18425-74-6]. These... 

Naphthaleneamine. 1-Naphthylamine or a-naphth5iamine/7i5 -i2- can be made from 1-nitronaphthalene by reduction with iron—dilute HCl, or by catalytic hydrogenation it is purified by distillation and the content of 2-naphthylamine can be reduced as low as 8—10 ppm. Electroreduction of 1-nitronaphthalene to 1-naphthylamine using titania—titanium composite electrode has been described (43). Photoinduced reduction of 1-nitronaphthalene on semiconductor (eg, anatase) particles produces 1-naphthylamine in 77% yield (44). 1-Naphthylamine/7J4-J2-. can also be prepared by treating 1-naphthol with NH in the presence of a catalyst at elevated temperature. The sanitary working conditions are improved by gas-phase reaction at... 

H-acid, l-hydroxy-3,6,8-ttisulfonic acid, which is one of the most important letter acids, is prepared as naphthalene is sulfonated with sulfuric acid to ttisulfonic acid. The product is then nitrated and neutralized with lime to produce the calcium salt of l-nitronaphthalene-3,6,8-ttisulfonic acid, which is then reduced to T-acid (Koch acid) with Fe and HCl modem processes use continuous catalytical hydrogenation with Ni catalyst. Hydrogenation has been performed in aqueous medium in the presence of Raney nickel or Raney Ni—Fe catalyst with a low catalyst consumption and better yield (51). Fusion of the T-acid with sodium hydroxide and neutralization with sulfuric acid yields H-acid. Azo dyes such as Direct Blue 15 [2429-74-5] (17) and Acid... 

Koch acid [117 2-0] 8-nitronaphthalene- 1,3,6-trisulfoni c acid iron... 

The oxidation of 1-nitronaphthalene by ceric ammonium nitrate has been reported (16). The resulting 1-iiitronaphthoquinone condenses with 1,3-butadiene followed by air oxidation under alkaline conditions to form 1-nitroanthraquinone, or l-aminoanthraquinone is formed direcdy by an intramolecular redox reaction. 

Amino-4-nitronaphthalene [776-34-1] M 188.2, m 195°, pK 0.54. Crystd from EtOH or ethyl acetate. 

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