Ketones
Ketones
Ketones are a class of compounds with the carbonyl group bonded to two other organic fragments through carbon [R(C=O)R’], wherein R and R’ are organic fragments bonded through carbon)]. Ketones are either pleasant smelling liquids or odorless solids. Examples of ketones are acetophenone, acetone, butanone, propanone, cyclohexanone, and cyclopentanone. They are widely present in nature (camphor, carvone, progesterone, cortisone, etc). Ketones with the alpha-hydrogen atom in acidic or basic conditions undergo keto-enol tautomerization. The keto form is more stable than the enol form.
Ketones have various uses in chemistry, medicine and industry. In organic synthesis, ketones are employed in various reversible addition reactions such as the formation of hemiacetals, acetals, imines, enamines and cyanohydrins; and irreversible addition reactions such as reduction by complex metal hydrides and addition of organometallic reagents. Ketones undergo reactions such as Wolff-Kishner reduction and Clemmensen reduction which result in the formation of corresponding alkanes. They are also useful as protecting agents to protect diols in organic synthesis. As solvents, ketones are widely used in manufacturing explosives, lacquers, paints, textiles, varnishes, resins, coatings and nail-polish removers. Ketones can also be used in making plastics, perfumes, flavourings and dyes. Ketones are employed in liniments and in the manufacture of celluloid.
