Functional Groups

Functional Groups• An atom or group of atoms on a

molecule that always reacts in the same manner.

The functional groups we will study

• Halocarbons

• Alcohols

• Ethers

• Aldehydes

• Ketones

• Amines

• Carboxylic acids

• Esters

• Amides

Halocarbons•General form:

R XR is any chain or ring attached to the halogen

X is one of the halogens: Cl, F, Br, or I

Halocarbons•Alkyl halide

•Halogen(s) attached to any aliphatic compound.

CH2

Cl

CH CH3

Cl1,2-dichloropropane

Halocarbons•Aryl halide

•A halogen attached to any aromatic compound.

1,3-dichlorobenzene(m-dichlorobenzene)

Cl

Cl

Alcohols•General form:

R is any chain or ring attached to the hydroxyl group

O-H is a hydroxyl group

R O H

Naming alcohols

1. Count the carbon atoms.

2. The name used is the same as for alkanes.

3. Remove the –e ending and add –ol.

4. If necessary, identify the carbon atom to which the hydroxyl is attached.

CH3 O H 1 carbon: methane 1 carbon alcohol:

methanol

You try it!•Name this alcohol:

CH2 O HCH2

CH2CH2

CH3

1-Pentanol

You try it!•Name this alcohol:

3-Pentanol

CH3 CH2

CH CH2

CH3OH

Ethers•General Form:

R O R1

Note the central oxygen atom

Naming EthersCount the carbon atoms separately

on either side of the oxygen.Use the branch name for each side,

listed alphabetically.Add the word “ether” to complete the

name.

Naming Ethers1 carbon on left:2 carbons on right:

CH3 O CH2 CH3

methyl ethyl

oxygen atom in between

ethylmethyl ether

You try it!•Name this ether:

ethylpropyl ether

CH2 O CH2 CH2CH3

CH3

Aldehydes•General form:•Contains a carbonyl group with one hydrogen

C

O

R H

carbonyl group hydrogen

Naming AldehydesCount the carbon atoms.Use the same name as you would for

an alkane with the same number of carbons.

Remove the –e at the end and replace it with –al.

ethanal

C

O

CH3H

carbonyl group

2 carbons

hydrogen attached to carbonyl

Ethane – e + -al =

C

O

CH2

CH2 CH3

H

Name this aldehyde

You try it!

butanal

Ketones•General form:

C

O

R1R

carbonyl group

Chains or rings attached to either side of the carbonyl

Naming ketonesCount the carbon atoms.Use the name of the alkane with the

same number of carbons.Number the carbon atoms so that

you identify the carbon to which the carbonyl is attached.

Remove the –e and add –one.

Naming ketones

C

O

CH2CH3

CH3

carbonyl group

Four carbons = butane

butane – e + one = 2-butanone

carbonyl attached to 2nd carbon

Is a number really necessary for this ketone?

You try!•Name this ketone:

C

O

CH3CH3

propanone

Is a number necessary for this ketone?

Amines•Amines are simply ammonia molecules in which one or more hydrogen atoms have been substituted with a branch or ring.•General form:

NR R

1

R2

Central nitrogen atom

R, R1, and R2 are either hydrogen atoms, branches, or rings.

Naming AminesLook for the central nitrogen.Count the number of carbons on

each branch attached to the nitrogen.

List each branch by its name in alphabetical order.

Add the word “amine” to the end of the name.

Naming Amines

NCH3 H

CH2CH3

Central nitrogen

ethyl group

methyl group

ethylmethyl amine

Naming AminesCentral nitrogen

ethyl group

methyl group

ethyldimethyl amine

NCH3 CH2

CH3

CH3

You Try!•Name this amine:

NCH2

CH2

CH3

CH3

H

diethyl amine

Carboxylic Acids•General form:

C

O

O HR

carbonyl group hydroxyl group

When a carbonyl AND a hydroxyl are bonded together, it is known as a carboxyl group.

carboxyl group

Naming Carboxylic AcidsIdentify the carboxyl group.Count the carbon atoms.Begin with the name of the alkane

that has the same number of carbons.

Remove the –e and add –oic and the word “acid” to the name.

If necessary, identify the carbon to which the carboxyl group is attached.

Naming Carboxylic Acids

C

O

O HH

carboxyl group

1 carbon atom

methane – e + oic acid = methanoic acid

You Try!

C

O

O HCH2CH3

propanoic acid

Name this carboxylic acid

2-methylpropanoic acid

C

O

OCH

H

CH3

CH3

Name this carboxylic acid

2,3-dimethylpentanoic acid

CH

CH

CH3

C

O

OH

CH2

CH3

CH3

Noteworthy Carboxylic acids

C

O

OHH

methanoic acid

is called “formic acid”

C

O

OHCH3

ethanoic acid

is called “acetic acid”

Stinging ants use formic acid as a defense mechanism.

This is the acid found in vinegar.

Esters

•General Form:

C

O

OR

1R

Ester group

hydrogen is replaced by a chain or ring

Naming EstersName the alkyl group Identify the ester group and use the

acid name.Remove the –ic and add –ate to the

end.

Naming Esters

C

O

OCH3CH3

ethanoate group

methyl group

(acetate group)

methyl ethanoateor

methyl acetate

Naming Esters•Name this ester:

C

O

OCH2CH2

CH3

CH3

propanoate groupethyl group

ethyl propanoate

Amides•General form:

C

O

NR

H

H

The oxygen in the carboxyl group is

replaced by a nitrogen atom bonded

to other atoms.

Naming AmidesCount the carbons.Use the name of the alkane with the

same number of carbons.Replace the final –e with –amide.

Naming Amides

C

O

NCH2

H

HCH3

3 carbons = propane

propane – e + amide = propanamide

You Try!•Name this amide:

C

O

NCH2

H

HCH2

CH3

butanamide

CH3 C

O

N

H

C

CH

CH CH

CH

C OH

A Noteworthy Amide:

If you’ve ever had a headache, chances are that you’ve taken this. This is acetaminophen.

(Also labeled Tylenol.)