Acetanilide is an odourless
solid
Solid is one of the four fundamental states of matter (the others being liquid, gas, and plasma). The molecules in a solid are closely packed together and contain the least amount of kinetic energy. A solid is characterized by structural ...
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
A trade name, trading name, or business name, is a pseudonym used by companies that do not operate under their registered company name. The term for this type of alternative name is a "fictitious" business name. Registering the fictitious name w ...
Antifebrin.
Preparation and properties
Acetanilide can be produced by reacting
acetic anhydride with
aniline
Aniline is an organic compound with the formula C6 H5 NH2. 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 starti ...
:
:C
6H
5NH
2 + (CH
3CO)
2O → C
6H
5NHCOCH
3 + CH
3COOH
The preparation used to be a traditional experiment in introductory organic chemistry lab classes, but it has now been widely replaced by the preparation of either
paracetamol or
aspirin
Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and/or inflammation, and as an antithrombotic. Specific inflammatory conditions which aspirin is used to treat inc ...
, both of which teach the same practical techniques (especially
recrystallization of the product) but which avoid the use of aniline, a suspected
carcinogen
A carcinogen is any substance, radionuclide, or radiation that promotes carcinogenesis (the formation of cancer). This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes. Several radioactive subs ...
.
Acetanilide is slightly
soluble
In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution.
The extent of the solubi ...
in water, and stable under most conditions.
Pure crystals are plate shaped and appear colorless, white, or in between.
Applications
Acetanilide is used as an
inhibitor of
hydrogen peroxide
Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3%� ...
decomposition and is used to stabilize
cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell w ...
ester
In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides a ...
varnishes. It has also found uses in the intermediation in
rubber
Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, an ...
accelerator synthesis, dyes and
dye intermediate synthesis, and
camphor synthesis. Acetanilide is used for the production of 4-acetamidobenzenesulfonyl chloride, a key intermediate for the manufacture of the
sulfa drugs.
In the 19th century acetanilide was one of a large number of compounds used as experimental
photographic developer
In the processing of photographic films, plates or papers, the photographic developer (or just developer) is one or more chemicals that convert the latent image to a visible image. Developing agents achieve this conversion by reducing the silve ...
s.
Pharmaceutical use
Acetanilide was the first
aniline
Aniline is an organic compound with the formula C6 H5 NH2. 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 starti ...
derivative found to possess
analgesic as well as
antipyretic
An antipyretic (, from ''anti-'' 'against' and ' 'feverish') is a substance that reduces fever. Antipyretics cause the hypothalamus to override a prostaglandin-induced increase in temperature. The body then works to lower the temperature, which r ...
properties, and was quickly introduced into medical practice under the names of Antifebrin by A. Cahn and P. Hepp in 1886. But its (apparent) unacceptable toxic effects, the most alarming being
cyanosis due to
methemoglobinemia and ultimately liver and kidney damage,
[.] prompted the search for supposedly less toxic aniline derivatives such as
phenacetin.
[.] After several conflicting results over the ensuing fifty years, it was established in 1948 that acetanilide was mostly
metabolized
Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...
to
paracetamol (acetaminophen) in the human body, and that it was this metabolite that was responsible for the analgesic and antipyretic properties.
[Multiple sources:
*.
*
*.] The observed methemoglobinemia after acetanilide administration was ascribed to the small proportion of acetanilide that is
hydrolyzed to aniline in the body.
[The presence of aniline as an impurity in 19th century batches of acetanilide drugs cannot be ruled out. In this respect, paracetamol (acetaminophen) is safer than acetanilide, as (1) the corresponding impurity would be ]4-aminophenol
4-Aminophenol (or ''para''-aminophenol or ''p''-aminophenol) is an organic compound with the formula H2NC6H4OH. Typically available as a white powder, it is commonly used as a developer for black-and-white film, marketed under the name Rodinal.
R ...
, which is less toxic than aniline; and (2) ''in vivo'' hydrolysis of the amide group in paracetamol appears to be negligible. Acetanilide is no longer used as a drug, although the efficacy of its metabolite paracetamol (acetaminophen) is well known.
See also
*
Nitroacetanilide
Notes
References
External links
{{Authority control
Photographic chemicals
Withdrawn drugs