keton

Ketone, in chemistry, refers to a class of organic compounds characterized by a carbonyl group (C=O) bonded to two carbon-containing substituents. The general structure is R-CO-R', where R and R' may be alkyl or aryl groups. The simplest ketone is acetone, or propanone. Ketones are named by replacing the final -e of the corresponding alkane with -one, with the carbonyl carbon given the lowest possible locant; common examples include cyclohexanone, acetophenone, and benzophenone.

Ketones are typically polar and have higher boiling points than alkanes of similar molecular weight due to the C=O dipole. They are generally immiscible with water in larger molecules, though many small ketones, such as acetone, are miscible with water. The carbonyl group is reactive toward nucleophiles; ketones undergo addition reactions, and the alpha position is enolizable, enabling aldol condensations and Michael additions. They can be prepared by oxidation of secondary alcohols or by Friedel–Crafts acylation of arenes with acyl chlorides.

In industry, acetone is a major solvent and chemical feedstock. Ketones also occur as metabolites; in biology, ketone bodies (acetoacetate, beta-hydroxybutyrate, and acetone) are produced in the liver during fasting or carbohydrate shortage and serve as alternative energy sources for the brain and other tissues.

Safety: ketones vary in flammability and toxicity; acetone is highly flammable and should be handled with care.