Alcohols, Phenols, Thiols, and Ethers

1
Chapter 14

• Alcohols, Phenols, Thiols, and Ethers

2
Nomenclature

• Find longest chain that contains OH
• Change e to ol in alkane
• Numbering begins at end nearest OH
• -OH takes precedence over double and triple bonds
  (Oxygen has higher atomic weight)
• 2 OH groups diol
• 3 OH groups triol

3-ethyl-4-methyl-2-heptanol
3
Phenols Benzene OH

• Carbon 1 is that bonded to OH
• Other substituents are named relative to the OH
• Use of ortho, meta, para for common names

3-propylphenol (meta-propylphenol)
4
Thiols Trade your -OH for -SH

• Nomenclature
• Add thiol to alkane name

e.g.,
3-ethyl-4-methyl-2-heptanethiol
5
Some examples

• Give IUPAC names for

2, 4-dichlorophenol
3-ethylpentanol
4-butyl-1-methylcyclohexanethiol
2, 4-dimethylcyclopentanol
6
Important Alcohols

• CH3OH Methanol wood alcohol
• DO NOT INGEST
• CH3CH2OH Ethanol
• Ingest at will, within reason
• Glycerol
• Base of trigylcerides
• (fatty acids)

1, 2, and 3 alcohols
7
Ethers Nomenclature

• Usually called by common name
• Alkoxy-
• CH3-O-CH2-CH3
• 1-methoxyethane (IUPAC name)
• Or
• Name both alkanes, then ether
• Ethyl methyl ether (common name)

8
Physical properties
H-bonds

• Hydrogen bonds between water and alcohol
• increase solubility in water
• raise boiling points

9
Summary of Physical Properties

• Alcohols (including phenols) are more soluble in
  water than corresponding alkane (or ether)
• BUT
• The LONGER the carbon chain, the LESS soluble
  Non-polar carbon atoms make molecule non-polar
• Alcohols have HIGH boiling points.

Both properties stem from H-bonding
10
The part you love ReactionsAlcohols
1. Dehydration reaction

• Alcohol Acid (with heat)

Alkene water acid
11
Dehydration of Alcohols, continued

• Saytzeffs Rule The poor get poorer

12
The part you love ReactionsAlcohols
2. Ether-forming reactions
1-butanol
1-butanol
Dibutyl ether
13
Oxidation of alcohols

• Oxidation in Organic chemistry may be defined as
• Forming bonds to oxygen or
• Breaking bonds to hydrogen
• 1, 2, 3 react differently

14
Oxidation of alcohols, continued
15
Oxidation of alcohols, continued

• Secondary alcohol oxidation
• 2 alcohol ? ketone

16
Practical Implications
Cr6 (Orange)
oxidation
Cr3 (Green)
Breathalyzer Test
17
Oxidation of Thiols

• Thiol ? disulfide bond

thiol
disulfide
18
Reaction Review

• Intramolecular dehydration
• ROH ? alkene water (acid and heat)
• Intermolecular dehydration
• ROH ? ROR (ether) water (acid and heat)
• Combustion of ROH
• ROH O2 ? CO2 H2O
• Oxidation of ROH
• Primary alcohol ? aldehyde
• Secondary alcohol ? ketone
• Tertiary ? no reaction
• Oxidation of Thiols
• Thiol ? disulfide