Aminophenol
Encyclopedia
4-Aminophenol is the organic compound
with the formula
H2NC6H4OH. Typically available as a white powder, it is commonly used as a developer in 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 isomer
ic aminophenols, the other two being 2-aminophenol
and 3-aminophenol
.
by nitration
followed by reduction with iron. Alternatively, the partial hydrogenation
of nitrobenzene
affords phenylhydroxylamine
, which rearranges primarily to 4-aminophenol:
. Treating p-aminophenol with acetic anhydride
gives paracetamol:
Organic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
with the formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
H2NC6H4OH. Typically available as a white powder, it is commonly used as a developer in black-and-white film, marketed under the name Rodinal
Rodinal
Rodinal is the trade name of a black and white developing agent produced originally by the German company Agfa based on the chemical 4-aminophenol.-History:Rodinal was patented January 27, 1891 by Dr. Momme Andresen...
.
Reflecting its slight hydrophilic character, the white powder is moderately soluble in alcohols and can be recrystallised
Recrystallization (chemistry)
-Chemistry:In chemistry, recrystallization is a procedure for purifying compounds. The most typical situation is that a desired "compound A" is contaminated by a small amount of "impurity B". There are various methods of purification that may be attempted , which includes recrystallization...
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 isomer
Isomer
In chemistry, isomers are compounds with the same molecular formula but different structural formulas. Isomers do not necessarily share similar properties, unless they also have the same functional groups. There are many different classes of isomers, like stereoisomers, enantiomers, geometrical...
ic aminophenols, the other two being 2-aminophenol
2-Aminophenol
2-Aminophenol is an organic compound with the formula C6H4NH2. 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...
and 3-aminophenol
3-Aminophenol
3-Aminophenol is a compound with formula C6H4. It is an aromatic amine and aromatic alcohol. It is an isomer of 2-aminophenol and 4-aminophenol....
.
Preparation
It is produced from phenolPhenol
Phenol, also known as carbolic acid, phenic acid, is an organic compound with the chemical formula C6H5OH. It is a white crystalline solid. The molecule consists of a phenyl , bonded to a hydroxyl group. It is produced on a large scale as a precursor to many materials and useful compounds...
by nitration
Nitration
Nitration is a general chemical process for the introduction of a nitro group into a chemical compound. The dominant application of nitration is for the production of nitrobenzene, the precursor to methylene diphenyl diisocyanate...
followed by reduction with iron. Alternatively, the partial hydrogenation
Hydrogenation
Hydrogenation, to treat with hydrogen, also a form of chemical reduction, is a chemical reaction between molecular hydrogen and another compound or element, usually in the presence of a catalyst. The process is commonly employed to reduce or saturate organic compounds. Hydrogenation typically...
of nitrobenzene
Nitrobenzene
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 as a precursor to aniline. Although occasionally used as a flavoring or perfume...
affords phenylhydroxylamine
Phenylhydroxylamine
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, is C6H5ONH2.-Preparation and derivatives:This...
, which rearranges primarily to 4-aminophenol:
- C6H5NO2 + 2 H2 → C6H5NHOH + H2O
- C6H5NHOH → HOC6H4NH2
Uses
p-Aminophenol is a building block compound. Prominently, it is the final intermediate in the industrial synthesis of paracetamolParacetamol
Paracetamol INN , or acetaminophen USAN , is a widely used over-the-counter analgesic and antipyretic . It is commonly used for the relief of headaches and other minor aches and pains and is a major ingredient in numerous cold and flu remedies...
. Treating p-aminophenol with acetic anhydride
Acetic anhydride
Acetic anhydride, or ethanoic anhydride, is the chemical compound with the formula 2O. Commonly abbreviated Ac2O, it is the simplest isolatable acid anhydride and is a widely used reagent in organic synthesis...
gives paracetamol:
