1. Chemsheets AS006 (Electron arrangement)
13/05/2019
ALDEHYDES & KETONES
© A June-2016

2. ALDEHYDES methanal ethanal propanal 3-methylbutanal
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3. KETONES propanone butanone pentan-3-one 4-methylpentan-2-one
© A June-2016

4. OXIDATION & REDUCTION
© A June-2016

5. OXIDATION & REDUCTION Tollen’s reagent, contains [Ag(NH3)2]+
Used to test for aldehydes – gives silver mirror
Reduced from Ag(+1) to Ag(0)

6. OXIDATION & REDUCTION Fehling’s solution, contains Cu(+2)
Used to test for aldehydes – gives brick-red precipitate of Cu2O
Reduced from Cu(+2) to Cu(+1)

7. OXIDATION & REDUCTION Acidified potassium dichromate, contains Cr2O72-
Used to test for alcohols (1y and 2y) & aldehydes – goes from orange Cr2O72- to green Cr3+
Reduced from Cr(+6) to Cr(+3)

8. OXIDATION & REDUCTION Distillation Reflux
Aldehyde condenses back into reaction mixture and reacts further
Alcohols and carboxylic acids (have hydrogen bonds between molecules) have higher bpts than aldehydes – so aldehyde can be distilled out as formed

9. NUCLEOPHILIC ADDITION
 –
Addition reactions: atoms add across C=O to the C and O
C is + so attacked by nucleophiles (electron pair donors)
The three atoms attached to the C are planar
© A June-2016

10. NUCLEOPHILIC ADDITION
Reduction with NaBH4
© A May-2016

11. NUCLEOPHILIC ADDITION
e.g. ethanal + NaBH4
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12. NUCLEOPHILIC ADDITION
e.g. propanone + NaBH4
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13. NUCLEOPHILIC ADDITION
Reaction with KCN then acid
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14. NUCLEOPHILIC ADDITION
many hydroxynitriles contain chiral C
formed as racemic mixture (50/50 mixture of enantiomers)
as equal chance of attack from above & below plane
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15. © www.chemsheets.co.uk A2 1026 25-May-2016

16. NUCLEOPHILIC ADDITION
e.g. propanone + KCN then acid
© A May-2016

17. NUCLEOPHILIC ADDITION
e.g. propanal + KCN then acid
© A May-2016