Acetanilide

Acetanilide

Names
IUPAC names N-phenylacetamide N-phenylethanamide
Identifiers
CAS Number	103-84-4 Y
ChEBI	CHEBI:28884 Y
ChEMBL	ChEMBL269644 Y
ChemSpider	880 Y
EC Number	203-150-7
Jmol 3D model	Interactive image
KEGG	C07565 Y
UNII	SP86R356CC Y
InChI InChI=1S/C8H9NO/c1-7(10)9-8-5-3-2-4-6-8/h2-6H,1H3,(H,9,10) Y Key: FZERHIULMFGESH-UHFFFAOYSA-N Y InChI=1/C8H9NO/c1-7(10)9-8-5-3-2-4-6-8/h2-6H,1H3,(H,9,10) Key: FZERHIULMFGESH-UHFFFAOYAA
SMILES O=C(Nc1ccccc1)C
Properties
Chemical formula	C8H9NO
Molar mass	135.17 g·mol−1
Odor	Odorless
Density	1.219 g/cm3
Melting point	114.3 °C (237.7 °F; 387.4 K)
Boiling point	304 °C (579 °F; 577 K)
Solubility in water	<0.56 g/100 mL (25 °C)
Solubility	Soluble in ethanol, diethyl ether, acetone, benzene
log P	1.16 (23 °C)
Vapor pressure	2 Pa (20 °C)
Dipole moment	2.71
Vapor pressure	{{{value}}}
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y verify (what is YN ?)
Infobox references

Drying acetanilide

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.

Preparation and properties

Acetanilide can be produced by reacting acetic anhydride with aniline:

C₆H₅NH₂ + (CH₃CO)₂O → C₆H₅NHCOCH₃ + CH₃COOH

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, both of which teach the same practical techniques (especially recrystallization of the product) but which avoid the use of aniline, a suspected carcinogen.

Acetanilide is slightly soluble in water, and stable under most conditions. Pure crystals are plate shaped and colorless to white.

Applications

Acetanilide is used as an inhibitor of hydrogen peroxide decomposition and is used to stabilize cellulose ester varnishes. It has also found uses in the intermediation in rubber 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. It is also a precursor in the synthesis of penicillin and other pharmaceuticals.

In the 19th century acetanilide was one of a large number of compounds used as experimental photographic developers.

Pharmaceutical use

Acetanilide was the first aniline derivative serendipitously found to possess analgesic as well as antipyretic properties, and was quickly introduced into medical practice under the name of Antifebrin by A. Cahn and P. Hepp in 1886. But its (apparent) unacceptable toxic effects, the most alarming being cyanosis due to methemoglobinemia, 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 to paracetamol (USAN: acetaminophen) in the human body, and that it was the paracetamol that was responsible for the analgesic and antipyretic properties. The observed methemoglobinemia after acetanilide administration was ascribed to the small proportion of acetanilide that is hydrolyzed to aniline in the body. Acetanilide is no longer used as a drug in its own right, although the success of its metabolite – paracetamol (acetaminophen) – is well known.