ketoniyhdisteet

Ketoniyhdisteet are organic compounds that contain a carbonyl group (C=O) bonded to two carbon atoms. This functional group, the ketone, is the defining characteristic of the class. The general formula for acyclic ketones is R-CO-R', where R and R' are alkyl or aryl groups. Ketones are distinct from aldehydes, where the carbonyl group is bonded to at least one hydrogen atom.

The physical properties of ketones vary depending on their molecular size and structure. Smaller ketones, such as acetone (propanone), are typically colorless liquids with characteristic, often pleasant, odors. They are generally soluble in water and polar organic solvents due to the polarity of the carbonyl group. As the hydrocarbon chains (R and R') lengthen, ketones become less polar and less soluble in water, and their boiling points increase.

Ketones are important in organic chemistry as intermediates in various reactions. The carbonyl carbon is electrophilic, making it susceptible to nucleophilic attack. This reactivity allows ketones to participate in reactions like nucleophilic addition, reduction to alcohols, and condensation reactions. They are also found in nature, for example, in certain flavor compounds and hormones. Industrially, ketones like acetone are used as solvents and in the production of plastics and pharmaceuticals. Their characteristic smell makes some ketones useful in fragrances.