P-aminophenol

4-Aminophenol

Names
Preferred IUPAC name 4-Aminophenol
Other names p-Aminophenol (no longer recommended)
Identifiers
CAS Number	123-30-8 Y
3D model (JSmol)	Interactive image Interactive image
ChEBI	CHEBI:17602 Y
ChemSpider	392 Y
ECHA InfoCard	100.004.198
KEGG	C02372 Y
MeSH	Aminophenols
PubChem CID	403
UNII	R7P8FRP05V Y
InChI InChI=1S/C6H7NO/c7-5-1-3-6(8)4-2-5/h1-4,8H,7H2 Y Key: PLIKAWJENQZMHA-UHFFFAOYSA-N Y InChI=1/C6H7NO/c7-5-1-3-6(8)4-2-5/h1-4,8H,7H2 Key: PLIKAWJENQZMHA-UHFFFAOYAD
SMILES Oc1ccc(N)cc1 c1cc(ccc1N)O
Properties
Chemical formula	C6H7NO
Molar mass	109.126 g/mol
Appearance	colorless to reddish-yellow crystals
Density	1.13 g/cm3
Melting point	187.5 °C (369.5 °F; 460.6 K)
Boiling point	284 °C (543 °F; 557 K)
Solubility in water	1.5 g/100 mL (25 °C)
Solubility	very soluble in dimethylsulfoxide soluble in acetonitrile ethyl acetate acetone slightly soluble in toluene, diethyl ether, ethanol negligible in benzene, chloroform
log P	0.04
Acidity (pKa)	10.30
Structure
Crystal structure	orthorhombic
Thermochemistry
Std enthalpy of formation (ΔfHo298)	-190.6 kJ/mol
Hazards
EU classification (DSD) (outdated)	Carc. Cat. 2 Muta. Cat. 2 Repr. Cat. 3 Toxic (T)
R-phrases (outdated)	R20/21, R22, R40 R52, R54, R68
S-phrases (outdated)	S28, S36, S37 S60, S61
NFPA 704	1 2 0
Flash point	195 °C (383 °F; 468 K) (cc)
Lethal dose or concentration (LD, LC):
LD50 (median dose)	671 mg/kg
Related compounds
Related aminophenols	2-Aminophenol 3-Aminophenol
Related compounds	Aniline Phenol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

4-Aminophenol (or para-aminophenol or p-aminophenol) is the organic compound with the formula H₂NC₆H₄OH. Typically available as a white powder, it was commonly used as a developer for black-and-white film, marketed under the name Rodinal.

Reflecting its slight hydrophilic character, the white powder is moderately soluble in alcohols and can be recrystallised from hot water. In the presence of base, it oxidizes readily. The N-methyl and N,N-dimethyl derivatives are of commercial value.

The compound is one of three isomeric aminophenols, the other two being 2-aminophenol and 3-aminophenol.

It is produced from phenol by nitration followed by reduction with iron. Alternatively, the partial hydrogenation of nitrobenzene affords phenylhydroxylamine, which rearranges primarily to 4-aminophenol:

It can be produced from nitrobenzene by electrolytic conversion to phenylhydroxylamine, which spontaneously rearranges to 4-aminophenol.

p-Aminophenol is a building block compound. Prominently, it is the final intermediate in the industrial synthesis of paracetamol. Treating p-aminophenol with acetic anhydride gives paracetamol: