4-Nitroaniline, p-nitroanilineor1-amino-4-nitrobenzene is an organic compound with the formula C6H6N2O2. A yellow solid, it is one of three isomers of nitroaniline. It is an intermediate in the production of dyes, antioxidants, pharmaceuticals, gasoline, gum inhibitors, poultry medicines, and as a corrosion inhibitor.[3]
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| Names | |||
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| Preferred IUPAC name
4-Nitroaniline | |||
| Systematic IUPAC name
4-Nitrobenzenamine | |||
| Other names
p-Nitroaniline | |||
| Identifiers | |||
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3D model (JSmol) |
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| 508690 | |||
| ChEBI | |||
| ChEMBL | |||
| ChemSpider |
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| ECHA InfoCard | 100.002.555 
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| EC Number |
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| 27331 | |||
| KEGG | |||
PubChem CID |
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| RTECS number |
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| UNII | |||
| UN number | 1661 | ||
CompTox Dashboard (EPA) |
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| Properties | |||
| C6H6N2O2 | |||
| Molar mass | 138.12 g/mol | ||
| Appearance | yellow or brown powder | ||
| Odor | faint, ammonia-like | ||
| Density | 1.437 g/ml, solid | ||
| Melting point | 146 to 149 °C (295 to 300 °F; 419 to 422 K) (lit.) | ||
| Boiling point | 332 °C (630 °F; 605 K) | ||
| 0.8 mg/ml at 18.5 °C (IPCS) | |||
| Vapor pressure | 0.00002 mmHg (20°C)[1] | ||
| -66.43·10−6cm3/mol | |||
| Hazards | |||
| Occupational safety and health (OHS/OSH): | |||
Main hazards |
Toxic | ||
| GHS labelling: | |||
 
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| Warning | |||
| H301, H311, H331, H373, H412 | |||
| P260, P261, P264, P270, P271, P273, P280, P301+P310, P302+P352, P304+P340, P311, P312, P314, P321, P322, P330, P361, P363, P403+P233, P405, P501 | |||
| NFPA 704 (fire diamond) | |||
| Flash point | 199 °C (390 °F; 472 K) | ||
| Lethal dose or concentration (LD, LC): | |||
LD50 (median dose) |
3249 mg/kg (rat, oral) 750 mg/kg (rat, oral) 450 mg/kg (guinea pig, oral) 810 mg/kg (mouse, oral)[2] | ||
| NIOSH (US health exposure limits): | |||
PEL (Permissible) |
TWA 6 mg/m3 (1 ppm) [skin][1] | ||
REL (Recommended) |
TWA 3 mg/m3 [skin][1] | ||
IDLH (Immediate danger) |
300 mg/m3[1] | ||
| Safety data sheet (SDS) | JT Baker | ||
| Related compounds | |||
Related compounds |
2-Nitroaniline, 3-Nitroaniline | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |||
4-Nitroaniline is produced industrially via the amination of 4-nitrochlorobenzene:[3]
Below is a laboratory synthesis of 4-nitroaniline from aniline. The key step in this reaction sequence is an electrophilic aromatic substitution to install the nitro group para to the amino group. The amino group can be easily protonated and become a meta director. Therefore, a protection of the acetyl group is required. After this reaction, a separation must be performed to remove 2-nitroaniline, which is also formed in a small amount during the reaction.[4]
4-Nitroaniline is mainly consumed industrially as a precursor to p-phenylenediamine, an important dye component. The reduction is effected using iron metal and by catalytic hydrogenation.[3]
It is a starting material for the synthesis of Para Red, the first azo dye:[5]
Nitroaniline undergoes diazotization, which allows access to 1,4-dinitrobenzene[6] and nitrophenylarsonic acid.[7] With phosgene, it converts to 4-nitrophenylisocyanate.[8] [9]
When heated with sulfuric acid, it dehydrates and polymerizes explosively into a rigid foam.[10]
InCarbon snake demo, paranitroaniline can be used instead of sugar, if the experiment is allowed to proceed under an obligatory fumehood.[11] With this method the reaction phase prior to the black snake's appearance is longer, but once complete, the black snake itself rises from the container very rapidly.[12] This reaction may cause an explosion if too much sulfuric acid is used.[13]
The compound is toxic by way of inhalation, ingestion, and absorption, and should be handled with care. Its LD50 in rats is 750.0 mg/kg when administered orally. 4-Nitroaniline is particularly harmful to all aquatic organisms, and can cause long-term damage to the environment if released as a pollutant.[14]
