![]() These factors relate to the pervasiveness of ketones in perfumery and as solvents. Because of their inability to serve both as hydrogen-bond donors and acceptors, ketones tend not to "self-associate" and are more volatile than alcohols and carboxylic acids of comparable molecular weights. Ketones are not usually hydrogen-bond donors and cannot hydrogen-bond to themselves. Because the carbonyl group interacts with water by hydrogen bonding, ketones are typically more soluble in water than the related methylene compounds. Thus, ketones are nucleophilic at oxygen and electrophilic at carbon. The carbonyl group is polar because the electronegativity of the oxygen is greater than that for carbon. Ketones are also distinct from other carbonyl-containing functional groups, such as carboxylic acids, esters and amides. ![]() In aldehydes, the carbonyl is bonded to one carbon and one hydrogen and are located at the ends of carbon chains. Ketones differ from aldehydes in that the carbonyl group (C=O) is bonded to two carbons within a carbon skeleton. Ketones are trigonal planar around the ketonic carbon, with C–C–O and C–C–C bond angles of approximately 120°. ![]() The ketone carbon is often described as sp 2 hybridized, a description that includes both their electronic and molecular structure. Structure and properties Representative ketones, from the left: acetone, a common solvent oxaloacetate, an intermediate in the metabolism of sugars acetylacetone in its (mono) enol form (the enol highlighted in blue) cyclohexanone, precursor to nylon muscone, an animal scent and tetracycline, an antibiotic. For some common chemicals (mainly in biochemistry), keto refer to the ketone functional group. The positions of other groups are indicated by Greek letters, the α-carbon being the atom adjacent to carbonyl group.Īlthough used infrequently, oxo is the IUPAC nomenclature for the oxo group (=O) and used as prefix when the ketone does not have the highest priority. When the two alkyl groups are the same, the prefix "di-" is added before the name of alkyl group. However, according to the rules of IUPAC nomenclature, the alkyl groups are written alphabetically, for example ethyl methyl ketone. Traditionally the names of the alkyl groups were written in order of increasing complexity, for example methyl ethyl ketone. The derived 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. These nonsystematic names are considered retained IUPAC names, although some introductory chemistry textbooks use systematic names such as "2-propanone" or "propan-2-one" for the simplest ketone ( C H 3−C(= O)−CH 3) instead of "acetone". ![]() Typically, the position of the carbonyl group is denoted by a number, but traditional nonsystematic names are still generally used for the most important ketones, for example acetone and benzophenone. Īccording to the rules of IUPAC nomenclature, ketone names are derived by changing the suffix -ane of the parent alkane to -anone. The word ketone is derived from Aketon, an old German word for acetone. Examples include many sugars ( ketoses), many steroids (e.g., testosterone), and the solvent acetone. Many ketones are of great importance in biology and in industry. ![]() The simplest ketone is acetone (where R and R' is methyl), with the formula (CH 3) 2CO. Ketones contain a carbonyl group −C(=O)− (which contains a carbon-oxygen double bond C=O). In organic chemistry, a ketone / ˈ k iː t oʊ n/ is an organic compound with the structure R−C(=O)−R', where R and R' can be a variety of carbon-containing substituents. ![]()
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