In chemistry, a ketone (alkanone) is an organic compound with the structure RC(=O)R', where R and R' can be a variety of carbon-containing substituents. Ketones and aldehydes are simple compounds that contain a carbonyl group (a carbon-oxygen double bond). They are considered "simple" because they do not have reactive groups like −OH or −Cl attached directly to the carbon atom in the carbonyl group, as in carboxylic acids containing −COOH.〔http://www.chemguide.co.uk/organicprops/carbonyls/background.html〕 Many ketones are known and many are of great importance in industry and in biology. Examples include many sugars (ketoses) and the industrial solvent acetone.
==Nomenclature and etymology==
The word ''ketone'' derives its name from ''Aketon'', an old German word for acetone.〔http://www.etymonline.com/index.php?term=ketone Online Etymology Dictionary〕〔The word "ketone" was coined in 1848 by the German chemist Leopold Gmelin. See: Leopold Gmelin, ed., ''Handbuch der organischen Chemie: Organische Chemie im Allgemeinen'' … (Handbook of organic chemistry: Organic chemistry in general … ), 4th ed., (Heidelberg, (Germany): Karl Winter, 1848), volume 1, p. 40. From page 40: ''"Zu diesen Syndesmiden scheinen auch diejenigen Verbindungen zu gehören, die als ''Acetone im Allegemeinen'' (''Ketone?'') bezeichnet werden."'' (To these syndesmides
*, those compounds also seem to belong, which are designated as ''acetones in general'' (''ketones?'').") 〕
According to the rules of IUPAC nomenclature, ketones are named by changing the suffix ''-ane'' of the parent alkane to ''-anone''. The position of the carbonyl group is usually denoted by a number. For the most important ketones, however, traditional nonsystematic names are still generally used, for example acetone and benzophenone. These nonsystematic names are considered retained IUPAC names,〔List of retained IUPAC names (retained IUPAC names Link )〕 although some introductory chemistry textbooks use systematic names such as "2-propanone" or "propan-2-one" for the simplest ketone (CH3−CO−CH3) instead of "acetone".
The common names of ketones are obtained by writing separately the names of the two alkyl groups attached to the carbonyl group, followed by "ketone" as a separate word. The names of the alkyl groups are written alphabetically. When the two alkyl groups are the same, the prefix di- is added before the name of alkyl group. The positions of other groups are indicated by Greek letters, the α-carbon being the atom adjacent to carbonyl group. If both alkyl groups in a ketone are the same then the ketone is said to be symmetrical, otherwise unsymmetrical.
Although used infrequently, ''oxo'' is the IUPAC nomenclature for a ketone functional group. Other prefixes, however, are also used. For some common chemicals (mainly in biochemistry), ''keto'' or ''oxo'' refer to the ketone functional group. The term ''oxo'' is used widely through chemistry. For example, it also refers to an oxygen atom bonded to a transition metal (a metal oxo).
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