1. Aldehydes & Ketones

2. Goals for the Day…. Naming Aldehydes & Ketones
Physical Properties of Aldehydes & Ketones
Reactions of Aldehydes & Ketones

3. Aldehydes and Ketones Both contain a carbonyl group,
an aldehyde has a carbonyl carbon bonded to one H atom.
a ketone, has the carbonyl carbon bonded to two carbon groups.

4. Structural and Skeletal Formulas
Aldehyde
Ketone
Your book might use this abbreviation, but it is not really preferred…

5. Learning Check
Identify the following compounds as either an aldehyde or ketone. A. CH3—CH2—CH2—COH B. CH3—CH2—CO—CH2—CH2—CH3 C. D.

6. Solutions
A. CH3—CH2—CH2—COH aldehyde B. CH3—CH2—CO—CH2—CH2—CH3 ketone C. ketone D. aldehyde

7. Naming Aldehydes
Suffix becomes anal.
has a common name for the first four aldehydes that use the prefixes: form- (1C), acet- (2C), propion- (3C), and butyr- (4C), followed by -aldehyde.
Must be included in the longest chain of carbons (and is automatically carbon #1).

8. Your Book’s Guide to Naming Aldehydes

9. Learning Check: Try this in your Composition Book…
Give the IUPAC name of the following aldehydes… A.
CH3—CH—CH2—CH2—CHO Cl

10. Solution
carbon 1 4- chloro pentanal (note that the carbonyl carbon is automatically carbon 1). A.
CH3—CH—CH2—CH2—CHO Cl

11. Learning Check: Try this in your Composition Book…
Give the IUPAC name of the following aldehydes.

12. Solution
ortho ethyl benzaldehyde

13. Examples for you to try…

14. Answer…
4-butyl hexanal

15. Learning Check 4-Methylpentanal
Draw the condensed structural formulas for the following in your composition book….
4-Methylpentanal

16. Solution
4-Methylpentanal

17. Learning Check
Draw the condensed structural formulas for the following in your composition books… 2,3-Dichloropropanal

18. Solution B. 2,3-Dichloropropanal
Remember that the carbonyl carbon is carbon 1! 
B. 2,3-Dichloropropanal

19. Aldehydes in Flavorings
Several naturally occurring aldehydes are used as flavorings for foods and fragrances.
Benzaldehyde
(almonds)
Cinnamaldehyde (cinnamon)

20. Naming Ketones
The carbonyl carbon has to be included in the longest chain of carbons
The carbonyl carbon gets priority in the numbering
The suffix becomes -anone
2-butanone
Ethyl methyl ketone
Smallest possible…
2-propanone
acetone

21. Ketones with Common Names
IUPAC retains well-used but unsystematic names for a few ketones

22. Your Book’s Guide to Naming Ketones

23. Examples to try

24. Answer
3-butyl-2-octanone

25. Examples to try

26. Answer…
7-phenyl-2-nonanone

27. Learning Check 3-Methyl-2-butanone
Draw the condensed structural formulas for the following.
3-Methyl-2-butanone

28. Solution
Should look something like this… 3-Methyl-2-butanone

29. Ketones in Common Use
Solvent: nail polish remover (acetone, propanone, dimethylketone)

30. Polar Carbonyl Group
The polar carbonyl group provides dipole–dipole interactions.
The partial positive carbon is attracted to the partial negative charge on a second carbonyl oxygen.

31. Boiling Points Aldehydes and ketones have
dipole–dipole interactions between polar groups.
higher boiling points than alkanes and ethers of similar mass due to dipole–dipole interactions.
lower boiling points than alcohols of similar mass because they do not form hydrogen bonds.

32. Order of intermolecular forces…
Hydrogen Bonding (alcohols…hydrogen bonders)
Dipoles (Aldehydes and ketones…carbonyl compounds)
Van der Waals (everything has these)

33. Comparison of Boiling Points

34. Ranking m.p./b.p... ________>__________>__________>__________
Highest lowest

35. Ranking m.p./b.p... a b d c
________>__________>__________>__________
Highest lowest

36. Solubility of Aldehydes and Ketones in Water
with one to four carbons are soluble in water.
with five or more carbons are not very soluble in water.
form hydrogen bonds with water between the carbonyl oxygen and hydrogen atoms of water.

37. Boiling Points, Solubility of Aldehydes and Ketones

38. Water solubility (which will be soluble?)...

39. The compounds containing Oxygen & Nitrogen will be soluble in water (up to 6 carbons)
Note: The alkanes & alkenes are not water soluble…

40. Learning Check
Select the compound in each pair that would have the higher boiling point. Explain. A. An alcohol forms hydrogen bonds. B. There are dipole–dipole attractions between the carbonyl groups. C.
CH3—CH2—CH3 or
CH3—CH2—OH or
CH3—CH2—OH or
CH3—O—CH3

41. Solution
Higher Boiling Point Reason A. CH3—CH2—OH An alcohol forms hydrogen bonds. B. There are dipole–dipole attractions between the carbonyl groups. C. CH3—CH2—OH An alcohol forms hydrogen bonds, but an ether does not.
CH3—CH2—OH
An alcohol forms hydrogen bonds.
There are dipole–dipole attractions between the carbonyl groups.
CH3—CH2—OH
An alcohol forms hydrogen bonds, but an ether does not

42. A. CH3—CH2—CH3 B. CH3—CH2—OH C. D. Learning Check
Indicate if each of the following is or is not soluble in water.
A. CH3—CH2—CH3
B. CH3—CH2—OH C. D.

43. Solution
A. CH3—CH2—CH3
B. CH3—CH2—OH C. D.
not soluble in water
soluble in water
soluble in water
soluble in water

44. Oxidation Alcohols are easily oxidized to aldehydes or ketones.
Aldehydes are easily oxidized to carboxylic acids.
Ketones cannot be oxidized.

45. Oxidation

46. Tollens’ Test
Tollens’ reagent, which contains Ag+, oxidizes aldehydes but not ketones.
Ag+ is reduced to metallic Ag, during oxidation. Ag appears as a “mirror” in the test tube.

47. is used to distinguish between an aldehyde and ketone.
Tollens’ Test
Tollens’ Test
is used to distinguish between an aldehyde and ketone.
does not oxidize alcohols or ethers.

48. Learning Check
Write the condensed structural formula the following is mixed with Tollens’ reagent.
Butanal

49. Butanal will oxidize to butanoic acid..
Answer…
Butanal will oxidize to butanoic acid..

50. Learning Check
Write the condensed structural formula when the following is mixed with Tollens’ reagent.
Acetaldehyde

51. Solution Acetaldehyde will oxidize to acetic acid (ethanoic acid)
Ethanoic acid, acetic acid

52. Learning Check
Write the condensed structural formula when the following is mixed with Tollens’ reagent
C. Ethyl methyl ketone

53. Solution
Remember that there is no hydrogen to pull off of the carbon atom, so ketones do not oxidize (just like tertiary alcohols).

54. Cu2+ reacts with aldehydes that have an adjacent –OH group.
Benedict’s Test
In the Benedict’s test,
Cu2+ reacts with aldehydes that have an adjacent –OH group.
aldehydes are oxidized to carboxylic acids.
Cu2+ is reduced to give Cu2O(s).

55. Benedict’s Test
Because many sugars, such as glucose, contain this type of aldehyde grouping, Benedict’s reagent can be used to determine the presence of glucose in blood or urine.

56. Reduction of Aldehydes & Ketones
Aldehydes and ketones are reduced by hydrogen (H2) with a catalyst or sodium borohydride (NaBH4), thus
decreasing the number of carbon-oxygen bonds,
reducing aldehydes to primary alcohols, and
reducing ketones to secondary alcohols.

57. Reduction of Aldehydes and Ketones
Aldehydes gives primary alcohols
Ketones gives secondary alcohols

58. How reductions work….
The hydrogen from NaBH4 adds to the carbonyl carbon.
The resulting ion protonates from the water.

59. Complimentary to oxidations…
Tertiary alcohols cannot be formed (because there is no carbonyl that can be reduced to make them).

60. Try to give the product…

61. Something like this…

62. Try to give the product…

63. Something like this…

64. What would you need to start with to get this alcohol?

65. One way to draw the starting material…

66. Additional Practice for you after class…

67. Classify each as an aldehyde or ketone.
Learning Check
Classify each as an aldehyde or ketone. A. C. B. D.

68. Classify each as an aldehyde or ketone.
Solution
Classify each as an aldehyde or ketone. A. C. B. D.
Ketone
Aldehyde
Aldehyde
Ketone

69. Classify each as an aldehyde, ketone, alcohol, or ether.
Learning Check
Classify each as an aldehyde, ketone, alcohol, or ether.
B. CH3─O─CH3 A. D. C.

70. A. B. CH3─O─CH3 Ketone Ether C. D. Alcohol Aldehyde Solution
Classify each as an aldehyde, ketone, alcohol, or ether. A.
B. CH3─O─CH3
Ketone
Ether C. D.
Alcohol
Aldehyde

71. Give the IUPAC name for each structure below…

72. Solution A. B.
2-Pentanone; methyl propyl ketone C.
Cyclohexanone
3,3-Dimethylbutanal

73. Name each of the following.
Learning Check
Name each of the following. A. B. C.

74. Name each of the following.
Solution
Name each of the following. A.
Pentanal B.
3-Chloropropanal C.
2-Butanone