functional groups

Functional Groups

By Dr. Christophy

Functional Groups

• “Arrangements of atoms in an organic compound that is capable of characteristic chemical reactions.”

• Functional groups contain at least one atom that is not C or H, usually O or N or a halogen.

• R is used to represent a carbon/hydrogen chain. R’ is used to represent a chain that may be different on the same molecule.

Alkyl Halides

• Hydrocarbon in which a halogen is attached to a carbon chain.

• The halogen is named as a substituent group, just like ethyl or methyl.

• The halogen names are fluoro-, chloro-, bromo- and iodo-

Naming Examples – Alkyl Halides

Name this structure:

H3CH2C C

HCH3

Cl

Name this structure:

H3CH2C C

H

HC

Br

CH3

Br

Click here to see the answer Click here to see the answer

Alcohols

• An alcohol contains an “OH” group attached to a hydrocarbon.

CH

OH

R R'

Alcohols (cont.)

• Alcohols all have the ending “-ol”. • A number indicates to which carbon the

functional group is attached. The alcohol gets the lowest number possible.

• Example:

CH

OH

H3C CH3

2-propanol

Naming Examples - Alcohols

Name this alcohol:

CH

OH

CH2

CH

H2C

H2C

H3C CH3

CH3

Name this alcohol

CH

OH

CH2

CH3

CH

H3C

OH

Click here to see the answerClick here to see the answer

Types of Alcohols

• If the alcohol is attached to a carbon that is also attached to two hydrogens and one other carbon, that is a primary alcohol.

• If the alcohol is attached to a carbon that is also attached to one hydrogen and two other carbons, that is a secondary alcohol.

• If the alcohol is attached to a carbon that is also attached to no hydrogens just three other carbons, that is a tertiary alcohol.

Types of Alcohols (cont.)

Identify the following as primary, secondary and tertiary alcohols:

CH

OH

H3C CH3

H2C

H3C CH2

OH

H2C

H3C C

OH

CH3

CH3

Click for the answer

Ethers

• When the hydrogen in an alcohol is instead replaced by a hydrocarbon group, the result is an ether:

R'ORThe R groups may be the same or different

Naming Ethers

• Ethers are named by naming the hydrocarbon on either side of the oxygen.

• The R-group names are placed in alphabetical order.

• If the R-groups are the same, the prefix “di” is used.

• The last word in the name is “Ether”

Naming Examples: Ether

H2CO

H2C CH3H3C

H2CO

H2C

H2CH3C CH3

Click here to see the name


Ketones

• A ketone, like an alcohol, has a carbon attached to an oxygen. This time, however, the C and the O are connected by a double-bond.

• The C=O group is called a “carbonyl” group

C

O

R'R

Naming Ketones

• The suffix for a ketone is “-one”• Ketones are named the same way as any

other hydrocarbon, except the longest chain must contain the C=O group, and the final “e” on the end of the name is replaced by “-one”

• Number the carbon that contains the double-bonded “O” with the lowest number possible.

Naming Examples - Ketones

C

O

CH2

CH

H2CH3C

CH3

CH3

C

O

CHH3C

H2C

CH3

H2C

CH3



Aldehydes

• Aldehydes are ketones at the end of a chain.

• The ending for an aldehyde is “-al”• Since the carbonyl group is always at

the end, there is no need for a number.

CH

O

R

Naming Examples

CH

O

H2CH3C

CH

O

H3C

CH

O

H2C

CH2H2C

H3CClick here to see the name



Carboxylic Acids

• Carboxylic Acids are kind of a combination of an aldehyde and an alcohol.

C

O

O HR

Naming Carboxylic Acids

• The ending is always “-oic acid”

• Again, no number is needed because the group is always at the end.

Carboxylic Acid Examples

C

O

O HH

C

O

O HH2C

H2CH3C



Esters

• Esters are a combination of a ketone and an ether

• The general formula is:

C

O

OR R'

Naming An Ester

• Esters are just a little tricky to name.

• The name of the group AFTER the “O” is first.

• The second word in the name is the part that includes the carboxyl group and ends with “oate”

Naming Examples - Ester

C

O

OH2C CH3H3C

C

O

OH2C

H2C

H2C CH3

H2CH3C

Click here to see name

Click here to see name

Amines

• Amines contain a nitrogen attached to a carbon and one or more hydrogens

• Like alcohols, amines can be primary, secondary or tertiary.

N

R"

R R' Any of these R groups could be a hydrogen

Amides

• An amide is attached to a carbon that has a carbonyl group.

C

O

NR

H

R'

functional groups

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