Ketone

[2][3] According to the rules of IUPAC nomenclature, ketone names are derived by changing the suffix -ane of the parent alkane to -anone.

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.

Traditionally the names of the alkyl groups were written in order of increasing complexity, for example methyl ethyl ketone.

However, according to the rules of IUPAC nomenclature, the alkyl groups are written alphabetically, for example ethyl methyl ketone.

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.

One broad classification subdivides ketones into symmetrical and unsymmetrical derivatives, depending on the equivalency of the two organic substituents attached to the carbonyl center.

Ketones (and aldehydes) absorb strongly in the infra-red spectrum near 1750 cm−1, which is assigned to νC=O ("carbonyl stretching frequency").

Ketones may be distinguished from aldehydes by giving a negative result with Tollens' reagent or with Fehling's solution.

For example, a billion kilograms of cyclohexanone are produced annually by aerobic oxidation of cyclohexane.

Many other methods have been developed, examples include:[8] Ketones that have at least one alpha-hydrogen, undergo keto-enol tautomerization; the tautomer is an enol.

The acidity of the α-hydrogen also allows ketones and other carbonyl compounds to react as nucleophiles at that position, with either stoichiometric and catalytic base.

Ketones are also weak bases, undergoing protonation on the carbonyl oxygen in the presence of Brønsted acids.

[19][20] Although acids encountered in organic chemistry are seldom strong enough to fully protonate ketones, the formation of equilibrium concentrations of protonated ketones is nevertheless an important step in the mechanisms of many common organic reactions, like the formation of an acetal, for example.

An important set of reactions follow from the susceptibility of the carbonyl carbon toward nucleophilic addition and the tendency for the enolates to add to electrophiles.

Nucleophilic additions include in approximate order of their generality:[8] Ketones are cleaved by strong oxidizing agents and at elevated temperatures.

Their oxidation involves carbon–carbon bond cleavage to afford a mixture of carboxylic acids having lesser number of carbon atoms than the parent ketone.

Ketone bodies are elevated in the blood (ketosis) after fasting, including a night of sleep; in both blood and urine in starvation; in hypoglycemia, due to causes other than hyperinsulinism; in various inborn errors of metabolism, and intentionally induced via a ketogenic diet, and in ketoacidosis (usually due to diabetes mellitus).

Ketones are produced on massive scales in industry as solvents, polymer precursors, and pharmaceuticals.

The combustion of hydrocarbons is an uncontrolled oxidation process that gives ketones as well as many other types of compounds.