4-Aminophenol (or para-aminophenol or p-aminophenol) is an organic compound with the formula H2NC6H4OH. Typically available as a white powder,[3] it is commonly used as a developer for black-and-white film, marketed under the name Rodinal.
| |||
Names | |||
---|---|---|---|
Preferred IUPAC name
4-Aminophenol[1] | |||
Other names
| |||
Identifiers | |||
| |||
3D model (JSmol)
|
| ||
385836 | |||
ChEBI |
| ||
ChEMBL |
| ||
ChemSpider |
| ||
ECHA InfoCard | 100.004.198 | ||
EC Number |
| ||
2926 | |||
KEGG |
| ||
MeSH | Aminophenols | ||
PubChem CID
|
| ||
UNII |
| ||
UN number | 2512 | ||
CompTox Dashboard (EPA)
|
| ||
| |||
| |||
Properties | |||
C6H7NO | |||
Molar mass | 109.128 g·mol−1 | ||
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) | ||
1.5 g/100 mL | |||
Solubility |
| ||
log P | 0.04 | ||
Acidity (pKa) |
| ||
Structure | |||
orthorhombic | |||
Thermochemistry | |||
Std enthalpy of
formation (ΔfH⦵298) |
-190.6 kJ/mol | ||
Hazards | |||
GHS labelling: | |||
Warning | |||
H302, H332, H341, H410 | |||
P201, P202, P261, P264, P270, P271, P273, P281, P301+P312, P304+P312, P304+P340, P308+P313, P312, P330, P391, P405, P501 | |||
NFPA 704 (fire diamond) | |||
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).
verify (what is ?)
Infobox references
|
Reflecting its slightly hydrophilic character, the white powder is moderately soluble in alcohols and can be recrystallized from hot water. In the presence of a base, it oxidizes readily. The methylated derivatives N-methylaminophenol and N,N-dimethylaminophenol 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 (Bamberger rearrangement).[4]
It can be produced from nitrobenzene by electrolytic conversion to phenylhydroxylamine, which spontaneously rearranges to 4-aminophenol.[5]
4-nitrophenol can be reduced through a variety of methods, to yield 4-aminophenol. One method involves hydrogenation over a Raney Nickel catalyst. A second method involves selective reduction of the nitro group by Tin(II) Chloride in anhydrous ethanol or ethyl ethanoate. [6][7]
4-Aminophenol is a building block used in organic chemistry. Prominently, it is the final intermediate in the industrial synthesis of paracetamol. Treating 4-aminophenol with acetic anhydride gives paracetamol:[8][9][10]
It is a precursor to amodiaquine, mesalazine, AM404, parapropamol, B-86810 & B-87836 (c.f. WO 2001042204).
4-Aminophenol converts readily to the diazonium salt.[11]