The Carbonyl group

Aldehydes

ketones

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  • Created by: mariam
  • Created on: 14-11-10 22:06

Carbonyl Group

The carbonyl group

  • Dipole-dipole forces between the molecules
  • Boiling points higher than alkanes
  • Difference in electro-negativity ----> strongly polar
  • NUCLEOPHILIC reagents can attack the C+
  • contains double bonds so unsaturated ----> addition reactions are possible
  • most typical reactions are nucleophilic addition

 

  (http://web.pdx.edu/~wamserc/CH332W97/9gifs/9a.gif) CARBONYL GROUP

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Aldehydes and Ketones

Aldehyde- AL

  • the aldehyde group can occur at the end of the group

Ketones - ONE

  • A ketone fewer than 3 carbons is not possible

Solubility

  • short chain aldehyde and ketone's mix completely with water as h bonds form between O from the carbonyl group and H20
  • As chain length increases the carbonyl group gets less soluble
  • Short chain aldehyde's and ketone's are liquids - pleasant smells scent soaps and food

 

 

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Nucleophilic addition reactions

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Addition of Hydrogen Cyanide (ketone)

Addition of Hydrogen Cyanide (ketone)

 

 

 

 

 

 

 

 

  • Ketone's can't be oxidised as the C-C bond must be broken
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Addition of hydrogen cyanide (Aldehyde)

 

 

 

 

  • increased length of carbon chain by 1 carbon -----> HYDROXYNITRILE
  • Aldehyde's ---> oxidised to carboxylic acids----> oxidising agent K dichromate

 

  • In a aldehyde or unsymmetrical ketone, the HCN can attack above or below the flat C=O group
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Reduction

Reduction

  • reducing agents will reduce Aldehyde's and Ketone's to alcohols

 

  • 1 reducing agent NaBH4--------> generates H- NUCLEOPHILE HYDRIDE ION H-

 

  • C=O is reduced but not the C=C as it is repelled by HIGH ELECTRON DENSITY in the C=C BOND.

 

  • BUT the H- is attracted to the C+ of the C=O bond

 

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Reducing an Ketone (NUCLEOPHILIC ADDITION REACTION

Reducing an Ketone - NUCLEOPHILIC ADDITION REACTION

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Reducing an Aldehyde (NUCLEOPHILIC ADDITION REACTI

Reducing an Aldehyde - NUCLEOPHILIC ADDITION REACTION

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Reducing an Aldehyde (NUCLEOPHILIC ADDITION REACTI

Reducing an Aldehyde - NUCLEOPHILIC ADDITION REACTION

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