Ketones

Introduction:

• Ketones are a class of organic compounds.
• They are based on alkane hydrocarbons and are called alkanones.
• Ketones are identified by the functional group >C=O, known as the carbonyl group.

Functional Group:

• The functional group of ketones is >C=O, which consists of a carbon atom double-bonded to an oxygen atom.

General Formula:

• Ketones belong to a homologous series with the general formula CnH2n+1COCnH2n+1.

Position of the Functional Group:

• In ketones, the >C=O functional group is never located at the end of the carbon chain.
• The carbon chain is numbered to give the lowest number to the carbon atom of the carbonyl group.

Common Ketones:

• Here are some common ketones along with their molecular formulas and shortened structural formulas:

1. Propanone (Acetone): CH₃-CO-CH₃ (CH₃COCH₃)
2. Butanone (Methyl Ethyl Ketone): C₂H₅-CO-CH₃ (CH₃CH2-COCH₃)
3. Pentan-2-one: C₃H₇-CO-CH₃ (CH₃(CH2)2COCH₃)
4. Hexan-2-one: C₄H₉-CO-CH₃ (CH₃(CH2)3COCH₃)
5. Heptan-2-one: C₅H₁₁-CO-CH₃ (CH₃(CH2)4COCH₃)
6. Octan-2-one: C₆H₁₃-CO-CH₃ (CH₃(CH2)5COCH₃)

Naming Ketones:

• When naming ketones, the longest carbon chain containing the >C=O functional group is named first.
• The carbon atom of the carbonyl group is assigned the lowest possible number.

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Ketones

Example:

• Propanone has a three-carbon chain with the carbonyl group in the middle. Its name reflects this: CH₃COCH₃.