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Oxidation of alcohols and aldehydes

Oxidation of alcohols and aldehydes. L.O.: Recognise and name aldehydes and ketones . Describe the oxidation of alcohols (primary, secondary). http://drbravochemistry.wikispaces.com/ Test on Friday. CH 3. H. C = O. C = O. H. H. CARBONYL COMPOUNDS - STRUCTURE.

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Oxidation of alcohols and aldehydes

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  1. Oxidation of alcohols and aldehydes L.O.: Recognise and name aldehydes and ketones. Describe the oxidation of alcohols (primary, secondary)

  2. http://drbravochemistry.wikispaces.com/ • Test on Friday.

  3. CH3 H C = O C = O H H CARBONYL COMPOUNDS - STRUCTURE Structurecarbonyl groups consists of a carbon-oxygen double bond the bond is polar due to the difference in electronegativity DifferenceALDEHYDES - at least one H attached to the carbonyl group

  4. CH3 CH3 C2H5 H C = O C = O C = O C = O CH3 H CH3 H CARBONYL COMPOUNDS - STRUCTURE Structurecarbonyl groups consists of a carbon-oxygen double bond the bond is polar due to the difference in electronegativity DifferenceALDEHYDES - at least one H attached to the carbonyl group KETONES - two carbons attached to the carbonyl group

  5. or RCHO Aldehydes are named using the suffix –al. or HCHO is methanal Or C6H5CHO. Benzenecarbaldehyde

  6. Name this Aldehydes Ethanal Propanal 2-Methylpropanal

  7. Ketones are named using the suffix –one. Propanone (acetone)

  8. Name the following ketones Butanone 3-Pentanone 3-Hexanone 2-methyl-3-hexanone

  9. Oxidising alcohols Reaction conditions: 1. The oxidising agent is always acidified potassium dichromate written above the arrow like this: K2Cr2O7/H2SO4 2. The reactants are the alcohol and “[O]” symbolising the oxidation agent 3. Heat is always needed

  10. Potassium dichromate In its oxidised state it is a bright orange liquid

  11. Problem. CH3CH2OH reacts with potassium dichromate. • What are the organic products? • Which product has a higher boiling point? • How could you isolate the aldehyde?

  12. Reflux apparatus Clamp stand Cooling tube (tap water goes in at the top and out at the bottom continuously) Reaction container Heat source

  13. Further oxidation of a primary alcohol • Using a process known as REFLUX, the reaction contents are continually heated at their boiling point temperature, so HOTTER and LONGER heating then alcohol conversion to an aldehyde • Still uses acidified potassium dichromate Primary + Oxidising  Carboxylic + water alcoholagent acid

  14. Draw out the conversation of ethanol to ethanoic acid using the displayed formula

  15. Oxidation of secondary alcohols • Like primary alcohols, also require acidified potassium dichromate and heat (but not reflux) • Converts the alcohol into a ketone Write out, using displayed formula, the oxidation of hexan-2-ol to hexa-2-one

  16. Oxidation of tertiary alcohols • The carbon attaching to the OH doesn’t have any hydrogens attached to it, so these can’t be oxidised.

  17. Potassium dichromate colour changes

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