Functional Group

1
Functional Group

• Atom or group of atoms that replaces a hydrogen
  atom in a hydrocarbon.
• Functional groups give the molecule personality.

2
Functional Group

• Each functional group gives the molecule
  distinctive chemical physical properties.
• Molecules with functional groups contain at least
  one atom that is not C or H. Not hydrocarbons!

3
Names of molecules with functional group

• Derived from the name of the hydrocarbon with the
  same number of carbon atoms.

4
Halides or halocarbons or alkyl halides

• One or more H in an alkane is replaced with a
  halogen (F, Cl, Br, or I).
• General formula R-X.
• X is the halogen.
• R is the alkyl branch.

5
Properties of Halides

• Likely to be polar molecules, unless very
  symmetric.
• Dipole-dipole interactions.

6
Polar Molecules

• Have POLES.
• The electron cloud is lop-sided. One end of
  molecule is electron-rich the other
  electron-poor.
• Dipole-dipole interactions.

7
Polar Molecules

• Atoms in molecule have very different
  electronegativities.
• Molecule is not symmetrically shaped.

8
Properties of Halides

• Higher mp, bp, Hf, Hv than the corresponding
  alkanes.
• Lower rate of evaporation vapor pressure than
  the corresponding alkanes.

9
Alcohols

• One or more hydrogens in a hydrocarbon replaced
  with an ?OH group.
• General formula R-OH.
• The ?OH or hydroxyl group does NOT ionize in
  water.

10
Properties of Alcohols

• NONelectrolytes. No H or OH- ions in solution.
  
• Do NOT turn litmus red, etc.

11
Properties of Alcohols

• Contain O-H bond. Molecules tend to be polar.
  Dissolve in water.
• Hydrogen bonding takes place between alcohol
  molecules. Higher mp, bp than corresponding
  alkanes.

12
Naming Alcohols

• Replace final e of corresponding alkane name
  with ol.

13
Classification of alcohols by number of -OH
groups.

• Monohydroxy 1 -OH group.
• Dihydroxy 2 OH groups.
• Trihydroxy 3 -OH groups.

14
Further classification of monohydroxy alcohols by
carbon to which OH group attached.

• Primary OH group at end carbon.
• Secondary OH group on middle carbon.
• Tertiary OH group at branch-point carbon.

15
Ethers

• Contain an O atom bridge connecting 2 alkyl
  branches.
• General Formula R?O?R
• R R are alkyl groups (the 2 branches).
• R R can be same or different.

16
Properties of Ethers

• Tend to be nonpolar.

17
Naming Ethers

1. Name branches alphabetically.
2. Stick the word ether at the end.

18
Carbonyl Group

• C in a chain that has a double bond to an O.
• gtCO or ?C?

O
?
19
Aldehydes

• Contain a carbonyl group at the end of the chain.

20
Naming Aldehydes

• Replace final e of corresponding alkane name
  with al.

21
Ketones

• Contain a carbonyl group on a carbon atom inside
  the chain, not at the end.

22
Naming Ketones

• Replace final e of corresponding alkane name
  with one.

23
Properties of ketones

• Carbonyl group is quite polar. Tend to be
  soluble in both polar nonpolar solvents.

24
Organic Acids

• Contain a COOH group at the end of the molecule.
• -C-O-H

O
?
25
Organic Acids

• The H in the COOH group is acidic!
• -C-O-H

O
?
26
Properties of organic acids

• Turn litmus red.
• Electrolytes!
• -C-O-H

O
?
27
Naming organic acids

• Replace the final e of the corresponding alkane
  name with -oic acid

28
Esters

• Contain 2 oxygens!
• Bridge O in the middle of the chain.
• Carbonyl O right next door.

29
General formula of esters

• R-CO-OR
• R-C-O-R'

Bridge O
Carbonyl O
O
?
30
Naming Esters

1. Name alkyl branch next to bridge O.
2. Name branch with carbonyl group.
3. Replace e of corresponding alkane name with
   -oate.

31
Formation of Esters

• Format of esterification rxn
• Alcohol Org. Acid ? Ester H2O

32
Formation of Esters
H
O
H
H
H

• H?C?C?OH HO?C?C?C?H

?
?
?
?
?
?
?
?
?
H
H
H
H
O
H
H H H
?
?
?
?
?
?
H?C?C?O?C?C?C?H H2O
?
?
?
?
H
H H H
33
Amines

• Replace H in an alkane with NH2 group.
• Replace final e in alkane name with amine.
• gives location of NH2 group.
• Analogous to alcohols

34
Properties of Amines

1. Tend to smell really bad.
2. Contain N-H bond. Exhibit H-bonding between
   molecules.

35
Amides

1. Contain NH2 group bonded to a carbonyl group.
2. General formula R-C-NH2

O
?
36
Naming Amides

1. Find name of corresponding alkane.
2. Drop final -e add amide.
3. Never need a - Always at the end.

37
Amino Acids

1. Contain COOH group at end.
2. C right next door has NH2 or amino group.

38
Polymer

1. Large molecules made of chains of smaller units
   covalently bonded together.

39
Monomer

1. Each individual unit of a polymer

40
Polymerization

1. Reaction leading to formation of polymers