2-Nitroaniline

Chemical properties

orange solid

The Uses of 2-Nitroaniline

2-Nitroaniline is the main precursor to?phenylenediamines, which are converted to?benzimidazoles, a family of?heterocycles?that are key components in pharmaceuticals.

The Uses of 2-Nitroaniline

Dyestuff intermediate.

Production Methods

2-Chloronitrobenzene is heated with excess (10 mol/mol) strong aqueous ammonia in an autoclave. The temperature is gradually increased to 180 ℃ over 4 h and held there for 5 h more. The pressure builds up to around 4 MPa and is released to an ammonia recycle loop before the product is isolated by filtration and washing. The reaction is extremely exothermic, and too rapid heating or inadequate temperature control can result in a runaway reaction. Because of this hazard, I.G. Farbenindustrie developed a continuous amination unit for amination of chloronitrobenzenes; the process is summarized under 4-nitroaniline.

Synthesis Reference(s)

Journal of the American Chemical Society, 77, p. 5688, 1955 DOI: 10.1021/ja01626a066
Organic Syntheses, Coll. Vol. 1, p. 388, 1941

General Description

Orange solid with a musty odor. Sinks and mixes slowly with water.

Air & Water Reactions

Insoluble in water.

Reactivity Profile

2-Nitroaniline may be sensitive to prolonged exposure to light. Mixtures of 2-Nitroaniline with magnesium are hypergolic on contact with nitric acid. 2-Nitroaniline forms extremely explosive addition compounds with hexanitroethane. 2-Nitroaniline has a vigorous reaction with sulfuric acid above 392° F. 2-Nitroaniline is incompatible with acids, acid chlorides, acid anhydrides, chloroformates and strong oxidizers.

Hazard

Explosion risk. Toxic when absorbed by skin.

Health Hazard

Inhalation or ingestion causes headache, nausea, methemo- globinemia, vomiting, weakness, and stupor; cyanosis caused by contact usually develops in 4-6 hrs.; prolonged and excessive exposure may also cause liver damage. Contact with eyes or skin causes irritation; continued exposure may cause same symptoms as inhalation or ingestion.

Fire Hazard

Special Hazards of Combustion Products: Toxic oxides of nitrogen may form in fire.

Safety Profile

A poison. Moderately toxic by ingestion. Mildly toxic by skin contact. Mutation data reported. Mixtures with magnesium are hypergolic on contact with nitric acid. Forms extremely explosive addltion compounds with hexanitroethane. Vigorous reaction with sulfuric acid above 200°C. When heated to decomposition it emits toxic fumes of NOx. See also m- NITROANILINE, p-NITROANILINE, and ANILINE DYES.

Environmental Fate

Biological. Under aerobic and anaerobic conditions using a sewage inoculum, 2-nitroaniline degraded to 2-methylbenzimidazole and 2-nitroacetanilide (Hallas and Alexander, 1983). A Pseudomonas sp. strain P6, isolated from a Matapeake silt loam, did not grow on 2-nitroaniline as the sole source of carbon. However, in the presence of 4-nitroaniline, approximately 50% of the applied 2-nitroaniline metabolized to nonvolatile products which could not be identified by HPLC (Zeyer and Kearney, 1983). In activated sludge inoculum, following a 20-d adaptation period, no degradation was observed (Pitter, 1976).
Plant. 2-Nitroaniline was degraded by tomato cell suspension cultures (Lycopericon lycopersicum). Transformation products identified were 2-nitroanilino-β-D-glucopyranoside, β-(2- amino-3-nitrophenyl)glucopyranoside, and β-(4-amino-3-nitrophenyl)-glucopyranoside (Pogány et al., 1990).

Purification Methods

Crystallise the aniline from hot water (charcoal), then from aqueous 50% EtOH, or EtOH, and dry it in a vacuum desiccator. It has also been chromatographed on alumina, then recrystallised from *benzene. [Beilstein 12 IV 1563.]