4-Nitroaniline

4-Nitroaniline, p-nitroaniline or 1-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]

4-Nitroaniline

Names
Preferred IUPAC name 4-Nitroaniline
Systematic IUPAC name 4-Nitrobenzenamine
Other names p-Nitroaniline 1-Amino-4-nitrobenzene p-Nitrophenylamine
Identifiers
CAS Number	100-01-6 Y
3D model (JSmol)	Interactive image
Beilstein Reference	508690
ChEBI	CHEBI:17064 Y
ChEMBL	ChEMBL14282 N
ChemSpider	13846959 Y
ECHA InfoCard	100.002.555
EC Number	202-810-1
Gmelin Reference	27331
KEGG	C02126
PubChem CID	7475
RTECS number	BY7000000
UNII	1MRQ0QZG7G Y
UN number	1661
CompTox Dashboard (EPA)	DTXSID8020961
InChI InChI=1S/C6H6N2O2/c7-5-1-3-6(4-2-5)8(9)10/h1-4H,7H2 N Key: TYMLOMAKGOJONV-UHFFFAOYSA-N N InChI=1/C6H6N2O2/c7-5-1-3-6(4-2-5)8(9)10/h1-4H,7H2 Key: TYMLOMAKGOJONV-UHFFFAOYAW
SMILES c1cc(ccc1N)N(=O)=O
Properties
Chemical formula	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)
Solubility in water	0.8 mg/ml at 18.5 °C (IPCS)
Vapor pressure	0.00002 mmHg (20°C)[1]
Magnetic susceptibility (χ)	−66.43·10−6 cm3/mol
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Toxic
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H301, H311, H331, H373, H412
Precautionary statements	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)	2 1 0
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). N verify (what is YN ?) Infobox references

Synthesis

4-Nitroaniline is produced industrially via the amination of 4-nitrochlorobenzene:^[3]

ClC₆H₄NO₂ + 2 NH₃ → H₂NC₆H₄NO₂ + NH₄Cl

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]

Applications

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]

Synthesis of Para Red

It is also a precursor to 2,6-dichloro-4-nitroaniline, also used in dyes.

Laboratory use

Nitroaniline undergoes diazotization, which allows access to 1,4-dinitrobenzene^[6] and nitrophenylarsonic acid.^[7] With phosgene, it converts to 4-nitrophenylisocyanate.^{[8] [9]}

Carbon snake demonstration

When mixed with sulfuric acid and heated, it dehydrates and polymerizes explosively into a rigid foam. The exact composition of the foam is unclear, but the process is believed to involve acidic protonation as well as displacement of the amine group by a sulfonic acid moiety.^[10]

In Carbon 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]

Toxicity

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]

See also

• 2-Nitroaniline
• 3-Nitroaniline