Aldehydes

Ketones

Carbonyl group

C

=O

Aldehydes Ketones Carboxylic acids Esters

CH3COCH2CH3

ONaOH

H2OCH3CO

-Na+O

CH3CH2OH

Sodiumhydroxide

+ +

Ethyl acetate Sodiumacetate

Ethanolheat

• In an aldehyde, at least one H atom is attached to a carbonyl group.

• In a ketone, two carbon groups are attached to a carbonyl group.

Aldehydes and Ketones

C=O

Step 1- Identify the rootSelect the longest carbon chain

that contains the carbonyl group (C=O). Name the parent alkane. Drop the –e on the parent alkane to get the root.

Step 2- Identify the suffixFor aldehydes, the suffix is –al

carbonyl group C=O is always C1, do not include the number in its name.

Step 4- Name the compoundCombine the prefix, root, and suffix to name the compound

Naming Aldehydes

Step 3- Identify the prefixNumber from the end nearest C=O group. Name and give

the position of any alkyl side groups as you for a hydrocarbon.

• Common names for the first two aldehydes use the prefixes “form” (1C) and “acet” (2C) followed by “aldehyde”.

O O O ║ ║ ║

H─C─H CH3─ C ─H CH3─CH2─ C ─H methanal ethanal propanal(formaldehyde) (acetaldehyde)

Naming Aldehydes

O ║CH3─CH─CH2─ C─H 3-Methylbutanal

O

║ Cl─CH2─CH2─ C─H 3-chloropropanal

CH3

1234

123

Name the following aldehydes

Root: hexan-

Suffix: -al

Prefix: 4-methyl

Name: 4-methylhexanal

CH36

5

4

3

21 O

CH3

H

Name the following aldehyde

• Root: decan• Suffix: -al• Prefix: 3-ethyl-6-methyl• Name:3-ethyl-6-methyldecanal

CH3

O

H

CH3

CH3

Draw 5-ethyl-4-methyloctanal

Root: eight carbons

Suffix: aldehyde

Prefix: methyl on C4, ethyl on C5

CH38

7

6

5

4

3

2

1

O

H

CH3

CH3

Step 1- Identify the rootSelect the longest carbon chain

that contains the carbonyl group (C=O). Name the parent alkane. Drop the –e on the parent alkane to get the root.

Step 2- Identify the suffixStart numbering at the end nearest the carbonyl group.

Determine number for carbonyl carbon. Suffix contains number for carbonyl carbon and -one

Step 4- Name the compoundCombine the prefix, root, and suffix to name the compound

Naming Ketones

Step 3- Identify the prefixName and give the position of any alkyl side groups as you for

a hydrocarbon.

Naming Ketones

O O

║ ║

CH3 ─ C ─CH3 CH3─C─CH2─CH3

propanone butan-2-one

1 2 3 4

Name the following ketone

• Root: hexan• Suffix:-2-one• Prefix:3,3-dimethyl

Name: 3,3-dimethylhexan-2-one

CH36 5

4

3

2

CH31

OCH3

CH3

Draw the structural formula for 5,5-dimethylheptan-3-one

Root: seven carbons

Suffix: carbonyl on C3

Prefix: two methyls on C5

CH37

6

5

4

3 2

CH31

O

CH3

CH3

Physical properties of Aldehydes and Ketones

1. They have strong odors (ketones have pleasant odors).

2. They are polar compounds.

3. Only dipole-dipole interactions (no hydrogen bonding).

4. Low boiling points compare to amines and alcohols.

5. Soluble in water (not soluble in nonpolar compounds).

δ+

δ-

δ+

δ-H

OHδ+

Hydrogen bond with water.

Higher than hydrocarbons.

C-O 3.5-2.5 = 1

Chemical properties of Aldehydes and Ketones

1. Oxidation: only for aldehydes (not for ketones).

K2Cr2O7

H2SO4

CH3─CH2─CH2─CH2─C─OH

=

O

CH3─CH2─CH2─CH2─C─H

=

O

Pentanal Pentanoic acidK2Cr2O7: Oxidizing agent