4-Aminophenol

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4-Aminophenol
P-Aminophenol.svg
4-Aminophenol3d.png
Names
Preferred IUPAC name
4-Aminophenol [1]
Other names
  • p-Aminophenol
  • para-Aminophenol
Identifiers
3D model (JSmol)
385836
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.004.198 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 204-616-2
2926
KEGG
MeSH Aminophenols
PubChem CID
UNII
UN number 2512
  • InChI=1S/C6H7NO/c7-5-1-3-6(8)4-2-5/h1-4,8H,7H2 Yes check.svgY
    Key: PLIKAWJENQZMHA-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/C6H7NO/c7-5-1-3-6(8)4-2-5/h1-4,8H,7H2
    Key: PLIKAWJENQZMHA-UHFFFAOYAD
  • Oc1ccc(N)cc1
  • c1cc(ccc1N)O
Properties
C6H7NO
Molar mass 109.128 g·mol−1
AppearanceColorless 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)
  • 5.48 (amino; H2O)
  • 10.30 (phenol; H2O) [2]
Structure
orthorhombic
Thermochemistry
-190.6 kJ/mol
Hazards
GHS labelling:
GHS-pictogram-exclam.svg GHS-pictogram-silhouette.svg GHS-pictogram-pollu.svg
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)
2
1
0
Flash point 195 °C (383 °F; 468 K) (cc)
Lethal dose or concentration (LD, LC):
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).
Yes check.svgY  verify  (what is  Yes check.svgYX mark.svgN ?)

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.

Contents

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.

Preparation

From phenol

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]

C6H5NO2 + 2 H2 → C6H5NHOH + H2O
C6H5NHOH → HOC6H4NH2

From nitrobenzene

It can be produced from nitrobenzene by electrolytic conversion to phenylhydroxylamine, which spontaneously rearranges to 4-aminophenol. [5]

From 4-nitrophenol

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]

Uses

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]

Synthesis of paracetamol from phenol.png

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]

Related Research Articles

<span class="mw-page-title-main">Aniline</span> Organic compound (C₆H₅NH₂); simplest aromatic amine

Aniline is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the simplest aromatic amine. It is an industrially significant commodity chemical, as well as a versatile starting material for fine chemical synthesis. Its main use is in the manufacture of precursors to polyurethane, dyes, and other industrial chemicals. Like most volatile amines, it has the odor of rotten fish. It ignites readily, burning with a smoky flame characteristic of aromatic compounds. It is toxic to humans.

<span class="mw-page-title-main">Nitrobenzene</span> Chemical compound

Nitrobenzene is an organic compound with the chemical formula C6H5NO2. It is a water-insoluble pale yellow oil with an almond-like odor. It freezes to give greenish-yellow crystals. It is produced on a large scale from benzene as a precursor to aniline. In the laboratory, it is occasionally used as a solvent, especially for electrophilic reagents.

<span class="mw-page-title-main">Hydroiodic acid</span> Solution of hydrogen iodide (HI) in water

Hydroiodic acid is an aqueous solution of hydrogen iodide (HI). It is a strong acid, one that is ionized completely in an aqueous solution. It is colorless. Concentrated solutions are usually 48% to 57% HI.

<span class="mw-page-title-main">Acetanilide</span> Chemical compound

Acetanilide is an odourless solid chemical of leaf or flake-like appearance. It is also known as N-phenylacetamide, acetanil, or acetanilid, and was formerly known by the trade name Antifebrin.

<span class="mw-page-title-main">Chlorobenzene</span> Aromatic organochlorine compound

Chlorobenzene is an aromatic organic compound with the chemical formula C6H5Cl. This colorless, flammable liquid is a common solvent and a widely used intermediate in the manufacture of other chemicals.

<span class="mw-page-title-main">Aromatic sulfonation</span>

Aromatic sulfonation is an organic reaction in which a hydrogen atom on an arene is replaced by a sulfonic acid functional group in an electrophilic aromatic substitution. Aryl sulfonic acids are used as detergents, dye, and drugs.

In organic chemistry, an azo coupling is an organic reaction between a diazonium compound and another aromatic compound that produces an azo compound. In this electrophilic aromatic substitution reaction, the aryldiazonium cation is the electrophile and the activated arene is a nucleophile. In most cases, including the examples below, the diazonium compound is also aromatic.

2-Chloroethanol (also called ethylene chlorohydrin or glycol chlorohydrin) is an organic chemical compound with the chemical formula HOCH2CH2Cl and the simplest beta-halohydrin (chlorohydrin). This colorless liquid has a pleasant ether-like odor. It is miscible with water. The molecule is bifunctional, consisting of both an alkyl chloride and an alcohol functional group.

<span class="mw-page-title-main">Phenylhydroxylamine</span> Chemical compound

Phenylhydroxylamine is the organic compound with the formula C6H5NHOH. It is an intermediate in the redox-related pair C6H5NH2 and C6H5NO. Phenylhydroxylamine should not be confused with its isomer α-phenylhydroxylamine or O-phenylhydroxylamine.

Nitrophenols are compounds of the formula HOC6H5−x(NO2)x. The conjugate bases are called nitrophenolates. Nitrophenols are more acidic than phenol itself.

The reduction of nitro compounds are chemical reactions of wide interest in organic chemistry. The conversion can be effected by many reagents. The nitro group was one of the first functional groups to be reduced. Alkyl and aryl nitro compounds behave differently. Most useful is the reduction of aryl nitro compounds.

The Béchamp reduction is a chemical reaction that converts aromatic nitro compounds to their corresponding anilines using iron as the reductant.

<span class="mw-page-title-main">Sulfanilic acid</span> Chemical compound

Sulfanilic acid (4-aminobenzenesulfonic acid) is an organic compound with the formula H3NC6H4SO3. It is an off-white solid. It is a zwitterion, which explains its high melting point. It is a common building block in organic chemistry.

4-Chloroaniline is an organochlorine compound with the formula ClC6H4NH2. This pale yellow solid is one of the three isomers of chloroaniline.

<span class="mw-page-title-main">2-Aminophenol</span> Chemical compound

2-Aminophenol is an organic compound with the formula C6H7NO. Along with its isomer 4-aminophenol, it is an amphoteric molecule and a reducing agent. It is a useful reagent for the synthesis of dyes and heterocyclic compounds. Reflecting its slight hydrophilic character, white powder is moderately soluble in alcohols and can be recrystallized from hot water.

p-Anisidine (or para-anisidine) is an organic compound with the formula CH3OC6H4NH2. A white solid, commercial samples can appear grey-brown owing to air oxidation. It is one of three isomers of anisidine, methoxy-containing anilines. It is prepared by reduction of 4-nitroanisole.

<span class="mw-page-title-main">4-Nitrochlorobenzene</span> Chemical compound

4-Nitrochlorobenzene is the organic compound with the formula ClC6H4NO2. It is a pale yellow solid. 4-Nitrochlorobenzene is a common intermediate in the production of a number of industrially useful compounds, including antioxidants commonly found in rubber. Other isomers with the formula ClC6H4NO2 include 2-nitrochlorobenzene and 3-nitrochlorobenzene.

4-Nitrotoluene or para-nitrotoluene is an organic compound with the formula CH3C6H4NO2. It is a pale yellow solid. It is one of three isomers of nitrotoluene.

<span class="mw-page-title-main">1,4-Dichloro-2-nitrobenzene</span> Chemical compound

1,4-Dichloro-2-nitrobenzene is an organic compound with the formula C6H3Cl2NO2. One of several isomers of dichloronitrobenzene, it is a yellow solid that is insoluble in water. It is produced by nitration of 1,4-dichlorobenzene. It is a precursor to many derivatives of commercial interest. Hydrogenation gives 1,4-dichloroaniline. Nucleophiles displace the chloride adjacent to the nitro group: ammonia gives the aniline derivative, aqueous base gives the phenol derivative, and methoxide gives the anisole derivative. These compounds are respectively 4-chloro-2-nitroaniline, 4-chloro-2-nitrophenol, and 4-chloro-2-nitroanisole.

In chemistry, the Halex process is used to convert aromatic chlorides to the corresponding aromatic fluorides. The process entails Halide exchange, hence the name. The reaction conditions call for hot solution of the aryl chloride and anhydrous potassium fluoride. Typical solvents are dimethylsulfoxide, dimethylformamide, and sulfolane. Potassium chloride is generated in the process. The reaction is mainly applied to nitro-substituted aryl chlorides.

References

  1. ↑ Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 690. doi:10.1039/9781849733069-FP001. ISBN   978-0-85404-182-4.
  2. ↑ Haynes, William M., ed. (2016). CRC Handbook of Chemistry and Physics (97th ed.). CRC Press. pp. 5–89. ISBN   978-1498754286.
  3. ↑ CRC Handbook of Chemistry and Physics 65th Ed.
  4. ↑ Mitchell, S.C. & Waring, R.H. "Aminophenols." In Ullmann’s Encyclopedia of Industrial Chemistry; 2002 Wiley-VCH, doi : 10.1002/14356007.a02_099
  5. ↑ Polat, K.; Aksu, M.L.; Pekel, A.T. (2002), "Electroreduction of nitrobenzene to p-aminophenol using voltammetric and semipilot scale preparative electrolysis techniques", Journal of Applied Electrochemistry, Kluwer Academic Publishers, 32 (2): 217–223, doi:10.1023/A:1014725116051, S2CID   54499902
  6. ↑ US2998450A,Godfrey, Wilbert&De, Angelis John,"Process of preparing nu-acetyl-p-amino phenol",issued 1961-08-29
  7. ↑ Bellamy, F. D.; Ou, K. (1984-01-01). "Selective reduction of aromatic nitro compounds with stannous chloride in non acidic and non aqueous medium". Tetrahedron Letters. 25 (8): 839–842. doi:10.1016/S0040-4039(01)80041-1. ISSN   0040-4039.
  8. ↑ Ellis, Frank (2002). Paracetamol: a curriculum resource. Cambridge: Royal Society of Chemistry. ISBN   0-85404-375-6.
  9. ↑ Anthony S. Travis (2007). "Manufacture and uses of the anilines: A vast array of processes and products". In Zvi Rappoport (ed.). The chemistry of Anilines Part 1 . Wiley. p.  764. ISBN   978-0-470-87171-3.
  10. ↑ Elmar Friderichs; Thomas Christoph; Helmut Buschmann. "Analgesics and Antipyretics". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a02_269.pub2.
  11. ↑ F. B. Dains, Floyd Eberly (1935). "p-Iodophenol". Organic Syntheses. 15: 39. doi:10.15227/orgsyn.015.0039.
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