Formula of Ketone:
A ketone (pronounced as key tone) is either the functional group characterized by a carbonyl group (O=C) linked to two other carbon atoms or a chemical compound that contains this functional group. A ketone can be generally represented by the formula:
A carbonyl carbon bonded to two carbon atoms distinguishes ketones from carboxylic acids, aldehydes, esters, amides, and other oxygen-containing compounds. The double-bond of the carbonyl group distinguishes ketones from alcohols and ethers. The simplest ketone is acetone (also called propanone).
The carbon atom adjacent to a carbonyl group is called the α-carbon. Hydrogens attached to this carbon are called α-hydrogens. In the presence of an acid catalyst the ketone is subjected to so-called keto-enol tautomerism. The reaction with a strong base gives the corresponding enolate. A diketone is a compound containing two ketone groups.
As solvents, ketones have the ability to dissolve other materials or substances, particularly polymers and adhesives. They are ingredients in lacquers, epoxies, polyurethane, nail polish remover, degreasers, and cleaning solvents. Ketones are also used in industry for the manufacture of plastics and composites and in pharmaceutical and photographic film manufacturing. Because they have high evaporation rates and dry quickly, they are sometimes employed in drying applications.
Some types of ketones used in industry, such as methyl isobutyl ketone and methyl ethyl ketone, are considered both hazardous air pollutants (HAP) and volatile organic compounds (VOC) by the EPA. As such, the Clean Air Act regulates their use.
In addition to these industrial sources, ketones are released into the atmosphere in cigarette smoke and car and truck exhaust. More "natural" environmental sources such as forest fires and volcanoes also emit ketones. Acetone, in particular is readily produced in the atmosphere during the oxidation of organic pollutants or natural emissions. Ketones (in the form of acetone, beta-hydroxybutyric acid, and acetoacetic acid) also occur in the human body as a byproduct of the metabolism, or break down, of fat.
Acetone, the simplest ketone
In general, ketones are named using IUPAC nomenclature by changing the suffix -e of the parent alkane to -one. For common ketones, some traditional names such as acetone and benzophenone predominate, and these are considered retained IUPAC names , although some introductory chemistry texts use names such as propanone.
Oxo is the formal IUPAC nomenclature for a ketone functional group. However, other prefixes are also used by various books and journals. For some common chemicals (mainly in biochemistry), keto or oxy is the term used to describe the ketone (also known as alkanone) functional group. Oxo also refers to a single oxygen atom coordinated to a transition metal (a metal oxo).
A carbonyl group is polar. This makes ketones polar compounds. The carbonyl groups interact with water by hydrogen bonding, and ketones are soluble in water. It is a hydrogen-bond acceptor, but not a hydrogen-bond donator, and cannot hydrogen-bond to itself. This makes ketones more volatile than alcohols and carboxylic acids of similar molecular weight.
The α-hydrogen of a ketone is far more acidic (pKa ≈ 20) than the hydrogen of a regular alkane (pKa ≈ 50). This is due to resonance stabilization of the enolate ion that is formed through dissociation. The relative acidity of the α-hydrogen is important in the enolization reactions of ketones and other carbonyl compounds.
Spectroscopy is an important means for identifying ketones. Ketones and aldehydes will display a significant peak in infrared spectroscopy, at around 1700 cm−1 (slightly higher or lower, depending on the chemical environment)
Ozonolysis of Alkenes