1. Chapter 13 Alcohols, Phenols, and Thiols
13.4 Reactions of Alcohols and Thiols

2. Combustion of Alcohols
Combustion is the reaction of an alcohol with O2 to produce CO2 and H2O.

3. Dehydration of Alcohols
Dehydration of an alcohol occurs
when heated with an acid catalyst
with the loss of —H and —OH from adjacent carbon atoms
alcohol
alkene

4. Saytzeff’s Rule According to Saytzeff’s rule, the dehydration of a
secondary alcohol favors the product in which
hydrogen is removed from the adjacent carbon atom in the chain with the smaller number of H atoms

5. Learning Check
Write the equations for the reactions when 2-propanol undergoes:
A. combustion
B. dehydration

6. Solution
A. dombustion:
B. dehydration:

7. Formation of Ethers
Ethers form when dehydration takes place at low temperature.
two methanol molecules
dimethyl ether

8. Oxidation and Reduction
In the oxidation of an organic compound,
there is an increase in the number of C—O bonds
there is a loss of H
In the reduction of an organic compound,
there is an decrease in the number of C—O bonds
there is a gain of H

9. Oxidation and Reduction (continued)

10. Oxidation of Primary (1) Alcohols
When a primary alcohol is oxidized [O],
one H is removed from the –OH
another –H is removed from the carbon bonded to –OH
an aldehyde is produced
Ethanol (ethyl alcohol)
Ethanal (acetaldehyde)

11. Oxidation of Secondary (2) Alcohols
When a secondary alcohol is oxidized [O],
one H is removed from the –OH
another –H is removed from the carbon bonded to the –OH
a ketone is produced
2-Propanone(dimethyl ketone,
“acetone”)
2-Propanol (isopropyl alcohol)

12. Oxidation of Tertiary (3) Alcohols
Tertiary alcohols do not readily oxidize.
There is no H on the C—OH to oxidize.
2-Methyl-2-propanol

13. Learning Check Select the compound that would result for each reaction
of CH3—CH2—CH2—OH.
1) CH3—CH ═ CH ) CO2 + H2O 3)
A. H+, heat
B. [O]
C. O2, heat

14. Solution Select the compound that would result for each reaction
of CH3—CH2—CH2—OH.
A. H+, heat 1) CH3—CH ═ CH2
B. [O] 3)
C. O2, heat 2) CO2 + H2O

15. Oxidation of Ethanol in the Body
ethanol is oxidized by enzymes in the liver
aldehyde product impairs coordination

16. Ethanol CH3─CH2─OH Ethanol acts as a depressant
kills or disables more people than any other drug
is metabolized at a rate of 12–15 mg/dL per hour by a social drinker
is metabolized at a rate of 30 mg/dL per hour by an alcoholic

17. Effect of Ethanol on the Body

18. Learning Check ? 1) CH3—CH ═ CH—CH3 2) 3) CO2 + H2O 4)
Select the product from the oxidation of
1) CH3—CH ═ CH—CH )
3) CO2 + H2O ) ?

19. Solution
Select the product from the oxidation of 2)

20. Oxidation of Thiols When thiols undergo oxidation,
an H atom is lost from two –SH groups
the product is a disulfide
disulfide