1. Alcohols, Phenols, and Thiols
General, Organic, and Biological Chemistry
Fourth Edition
Karen Timberlake
Chapter 13
Alcohols, Phenols, Thiols, and Ethers
13.1
Alcohols, Phenols, and Thiols
Lectures
© 2013 Pearson Education, Inc.

2. Alcohols, Phenols, and Thiols
An alcohol contains a hydroxyl group (–OH) attached to a carbon chain.
A phenol contains a hydroxyl group (–OH) attached to a benzene ring.
A thiol contains a thiol group (–SH) attached to a carbon chain. 2

3. Guide to Naming Alcohols3

4. Naming Alcohols The names of alcohols
in the IUPAC system, replace -e of the alkane name with -ol.
that are common names, use the name of the alkyl group followed by alcohol.
Formula IUPAC Common Name
CH4 Methane
CH3─OH Methanol Methyl alcohol
CH3─CH3 Ethane
CH3─CH2─OH Ethanol Ethyl alcohol 4

5. Naming Alcohols In IUPAC names for longer carbon chains, the chain is
numbered from the end nearer the –OH group. 5

6. Naming Alcohols We can also draw skeletal structures for alcohols.
CH3─CH2─CH2─OH CH3─CH─CH2─CH3 OH
1-Propanol Butanol 6

7. Phenols in Medicine Phenol
is the IUPAC name for benzene with a hydroxyl group.
is used in antiseptics and disinfectants.
Phenol Resorcinol Hexylresoricinol 7

8. Naming Phenols To name a phenol with two substituents,
assign C-1 to the carbon attached to the –OH.
number the ring to give the substituents the lowest numbers.
use prefixes o, m, and p for common names.
Phenol chlorophenol methylphenol
(m-chlorophenol) (m-cresol) 8

9. Thiols Thiols are organic compounds that contain a –SH group.
are named in the IUPAC system by adding thiol to the alkane name of the longest carbon chain. 9

10. Naming Thiols
In thiols with long carbon chains, the chain is numbered to give the −SH group the lowest possible number. 10

11. Ethers
Ethers consist of an oxygen atom that is connected by single bonds to two carbon groups (alkyl or aromatic).
Simple ethers are named by listing the alkyl names in alphabetical order followed by ether
CH3─O─CH3
CH3─CH2─O─CH3
methyl
methyl
ethyl
methyl 11

12. Cyclic Ethers A cyclic ether contains an O atom in a carbon ring.
is called a heterocyclic compound.
typically has 5 (furan) or 6 atoms (pyran) in the ring.
Furan Tetrahydrofuran Pyran ,4-Dioxane 12

13. Dioxins
Dioxins are
a six-atom ring with two oxygen atoms and two double bonds.
a group of ethers that are highly toxic and often carcinogenic.
formed during forest fires and as industrial by-products. 13

14. IUPAC Names for Ethers
In the IUPAC system, the shorter alkyl group and the oxygen are named as an alkoxy group attached to the longer alkane.
Methoxy propane
CH3—O—CH2—CH2—CH3
Numbering the longer alkane gives
1-Methoxypropane. 14

15. Guide to Naming Ethers 15

16. Classifying Alcohols 16

17. Boiling Points of Alcohols
form hydrogen bonds between alcohol molecules.
have higher boiling points than alkanes and ethers of similar mass. 17

18. Boiling Points of Ethers
have an O atom, but no H is attached.
cannot form hydrogen bonds between ether molecules.
have boiling points similar to alkanes of similar mass. 18

19. Solubility of Alcohols and Ethers in Water
Alcohols and ethers are more soluble in water than are alkanes because the oxygen atom can form hydrogen bonds with water.
Alcohol Solubility in H2O
1–3 carbon atoms completely soluble
4 carbon atoms slightly soluble
5 or more carbon atoms insoluble
Ethers containing up to 4 carbon atoms are slightly soluble in water. 19

20. Solubility of Alcohols and Ethers in Water20

21. Comparing Solubility and Boiling Points21

22. Combustion of Alcohols
Combustion is the reaction of an alcohol with O2 to
produce CO2, H2O and energy. 22

23. Dehydration of Alcohols
Dehydration of an alcohol occurs
when heated with an acid catalyst, H+
with the loss of –H and –OH from adjacent carbon atoms to form water
alcohol
alkene 23

24. Saytzeff’s Rule
According to Saytzeff’s rule, the dehydration of a secondary alcohol favors the product in which hydrogen is removed from the carbon atom in the chain with the smaller number of H atoms 24

25. 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 a decrease in the number of C–O bonds.
there is a gain of H. 25

26. Oxidation and Reduction
An alcohol is more oxidized than an alkane; an aldehyde or ketone is more oxidized than an alcohol; a carboxylic acid is more oxidized than an aldehyde. 26

27. Oxidation of Primary (1) Alcohols
Primary alcohols are oxidized to form aldheydes.
Ethanol (ethyl alcohol)
Ethanal (acetaldehyde) 27

28. Oxidation of Secondary (2) Alcohols
Secondary alcohols are oxidized to form ketones.
2-Propanol (isopropyl alcohol)
2-Propanone(dimethyl ketone,
“acetone”) 28

29. 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 29