Chapter 12 Organic Compounds with Oxygen and Sulfur

Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc.

Chapter 12 Organic Compounds with Oxygen and Sulfur

12.4 Aldehydes and Ketones

1


Carbonyl Group in Aldehydes and Ketones

A carbonyl group• consists of a carbon-oxygen polar

double bond• has a very electronegative oxygen

atom • has two lone pair electrons on the

O atom• has partial positive charge on C

and partial negative charge on O

2

C

O


Carbonyl Group in Aldehydes and Ketones

A carbonyl group• in an aldehyde is attached

to at least one H atom

• in a ketone is attached to two carbon groups

3


Naming Aldehydes

An aldehyde• has an IUPAC name in which the -e in the alkane name is

changed to -al• has a common name for the first four aldehydes that use the

following prefixes: 1 carbon, form 2 carbons, acet

3 carbons, propion 4 carbons butyr

followed by aldehyde

4


Naming Aldehydes5


Naming Aldehydes6


Naming Aldehydes7

Give the IUPAC name for the following aldehydes:

O ||CH3CH2CH2CHCH

| CH3

C

O

H

Cl

Cl


Naming Aldehydes8

Step 1 Name the longest carbon chain containing thecarbonyl group by replacing the e in the alkane name with al.

O ||CH3CH2CH2CHCH

| CH3

pentanal

C

O

H

Cl

Cl

benzaldehyde


Naming Aldehydes9

Step 2 Name and number substituents by counting the carbonyl group as carbon 1.

O ||CH3CH2CH2CHCH

| CH3

2-methylpentanal

C

O

H

Cl

Cl

3,4-dichlorobenzaldehyde


Aldehydes in Flavorings

Several naturally occurring aldehydes are used as flavorings for foods and fragrances.

10

C

O

H

C

O

H

OCH3

HO

HC CH

CH

O

benzaldehyde (almonds)

vanillin

cinnamaldehydecinnamon


Naming Ketones

When naming the following ketones• in the IUPAC system, the -e in the alkane name is replaced

with -one• with a common name, the alkyl groups attached to the

carbonyl group are named alphabetically, followed by ketone

O O

CH3 CCH3 CH3CCH2CH3

propanone 2-butanone (dimethyl ketone) (ethyl methyl ketone)

11


Naming Ketones12


Naming Ketones

Name the following ketones using the IUPAC system.

O ||

CH3CH2CHCH2CCH3

|

CH3

13

CH3

CH3

O


Naming Ketones

Step 1 Name the longest carbon chain that contains the carbonyl group by replacing the e in the alkane name with one.

O ||

CH3CH2CHCH2CCH3

|

CH3

hexanone

14

CH3

CH3

O

pentanone


Naming Ketones

Step 2 Number the carbon chain starting from the end nearer the carbonyl group and indicate its location.

O ||

CH3CH2CHCH2CCH3

|

CH3

2-hexanone

15

CH3

CH3

O

pentanone


Naming Ketones

Step 3 Name and number any substituents on the carbon chain.

O ||

CH3CH2CHCH2CCH3

|

CH3

4-methyl-2-hexanone

16

CH3

CH3

O

2,3-dimethylcylcopentanone


Ketones in Common Use17

Acetone (propanone) is a solvent used in nail polish remover.

Butanedione is the butter flavoring used in margarine.


Learning Check

Classify each as an aldehyde or ketone.

O O || ||

A. CH3—CH2—C—CH3 B. CH3—C—H

CH3 O | ||

C. CH3—C—CH2—C—H D. | CH3

18

O


Solution

Classify each as an aldehyde or ketone.

O O || ||

A. CH3—CH2—C—CH3 B. CH3—C—H

CH3 O | ||

C. CH3—C—CH2—C—H D. | CH3

19

aldehyde ketone

aldehydeketone

O


Learning Check

Classify each as an aldehyde, ketone, alcohol, or ether.

O A. CH3CH2CCH3 B. CH3OCH3

CH3 O OH C. CH3CCH2CH D. CH3CHCH3

CH3

20


Solution

Classify each as an aldehyde, ketone, alcohol, or ether.

O A. CH3CH2CCH3 B. CH3OCH3

CH3 O OH C. CH3CCH2CH D. CH3CHCH3

CH3

21

aldehyde alcohol

ketone ether


Learning Check

Give the IUPAC name for each of the following ketones.

O A. CH3CH2CH2CH2CCH3

O B. ClCH2CH2CCH3

22


Solution


Step 1 Name the longest carbon chain that contains the carbonyl group by replacing the e in the alkane name with one.

O A. CH3CH2CH2CH2CCH3 pentanone

O B. ClCH2CH2CCH3 butanone

23


Solution


Step 2 Name the carbon chain starting from the end nearer the carbonyl group and indicate its location.

O A. CH3CH2CH2CH2CCH3 2-pentanone

O B. ClCH2CH2CCH3 2-butanone

24


Solution


Step 3 Name and number any substituents on the carbon chain.

O A. CH3CH2CH2CH2CCH3 2-pentanone

O B. ClCH2CH2CCH3 4-chloro-2-butanone

25


Learning Check

Give the IUPAC name for the following aldehyde compounds.

O ||

A. CH3—CH2—CH2—C—H

CH3 O | ||

B. CH3—C—CH2—C—H | CH3

26


Solution


Step 1 Name the longest carbon chain containing the carbonyl group by replacing the e in the alkane name with al.

O ||

A. CH3—CH2—CH2—C—H butanal

CH3 O | ||

B. CH3—C—CH2—C—H butanal | CH3

27


Solution


Step 2 Name and number substituents by counting the carbonyl group as carbon 1.

O ||

A. CH3—CH2—CH2—C—H butanal

CH3 O | ||

B. CH3—C—CH2—C—H 3,3-dimethylbutanal | CH3

28


Learning Check

Draw the structural formulas for each:

A. 4-methylpentanal

B. 2,3-dichloropropanal

C. 3-methyl-2-butanone

29


Solution

Draw the structural formulas for each:

CH3 O A. 4-methylpentanal CH3CHCH2CH2CH

Cl O B. 2,3-dichloropropanal ClCH2CHCH

CH3 O

C. 3-methyl-2-butanone CH3CHCCH3

30

Chapter 12 Organic Compounds with Oxygen and Sulfur

Documents

Transcript of Chapter 12 Organic Compounds with Oxygen and Sulfur