2-Aminophenol

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2-Aminophenol
IUPAC name 2-Aminophenol
Other names 2-hydroxyaniline
2-amino-1-hydroxybenzene
Identifiers
CAS number [95-55-6]
SMILES Nc1ccccc1O
InChI InChI=1/C6H7NO/c7-5-3-1-2-4-6(5)8/h1-4,8H,7H2
Properties
Molecular formula C6H7NO
Molar mass 109.13 g/mol
Appearance White orthorhombic pyramidal needles
Density 1.328 g/cm³
Melting point

174 °C
Solubility in water slightly soluble in cold water, soluble in hot water
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)
Infobox disclaimer and references

2-Aminophenol is an organic compound with the formula C6H4(OH)NH2. 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. [1]. Reflecting its slight hydrophilic character, white powder is moderately soluble in alcohols and can be recrystallised from hot water.

Contents

[edit] Synthesis

2-Aminophenol (and its isomer, 4-aminophenol) is industrially synthesized by reducing the corresponding nitrophenol by hydrogen in the presence of various catalysts. The nitrophenols can also be reduced with iron.[1]

[edit] Structure

The compound contains an internal hydrogen bond between the neighbouring amine and hydroxyl groups that partly co-ordinates with the same groups on a neighbouring molecule as well. As a result, 2-aminophenol has a rather high melting point compared to other molecules with a similar molecular mass such as methylphenol.[2]

[edit] Applications

2-Aminophenol has a variety of uses. As a reducing agent, it is marketed under the names of Atomal and Ortol to develop black and white photographs.[1] 2-Aminophenol is an intermediate in the synthesis of dyes. It is particularly useful in yielding tridentate ligands for metal-complex dyes when diazotized and coupled to a phenol, naphthol, or other aromatic or resonant dye species. Metal complex dyes using copper or chromium are commonly used for producing dull colors. Tridentate ligand dyes are particularly useful, since they are more stable than their bi- or mono-dentate counterparts.[3],[4]

Due to the adjacency of the amino and hydroxyl groups, 2-aminophenol readily forms heterocycles. These heterocycles, such as benzoxazoles, can be biologically active and useful in the pharmaceutical industry:[1]

[edit] References

  1. ^ a b c d Mitchell, S.C. & Waring, R.H. “Aminophenols.” In Ullmann’s Encyclopedia of Industrial Chemistry; 2002 Wiley-VCH, doi:10.1002/14356007.a02_099 
  2. ^ Reference Handbook of Fine Chemicals, Acros Organics Publishers, Fisher Scientific UK, (2007), www.acros.com
  3. ^ Grychtol, K.; Mennicke, W. “Metal-Complex Dyes.” In Ullmann’s Encyclopedia of Industrial Chemistry; 2002 Wiley-VCH, DOI: 10.1002/14356007.a16_299
  4. ^ Hunger, K.; Mischke, P.; Rieper, W.; Raue, R.; Kunde, K.; Engel, A. “Azo Dyes.” In Ullmann’s Encyclopedia of Industrial Chemistry 2002 Wiley-VCH, DOI: 10.1002/14356007.a03_245