Ch. 12: Compounds
with O and S
Chem 20
El Camino College
1
Alcohols, Thiols, Ethers
O
H 3C
methanol
O
S
H
H3C
H
methanethiol
H3C
CH3
dimethyl ether
2
Naming Alcohols
Name the longest carbon chain containing the
OH group, use the –ol suffix
 Number the chain to give the OH the lowest
number
 Give the location and name of other substituents
in alphabetical order.

3
Name These
OH
H3C
CH2
CH2
CH2
OH
OH
1-butanol
2-butanol
3-pentanol
4
Name These
OH
OH
OH
Cl
3-methyl-2-pentanol
Br
2-bromo-2-chloro-1-butanol
2,2-dimethyl-1-butanol
5
Draw These
OH
3-methyl-2-butanol
CH3
2,2-dibromo-1-propanol
Br
Br
OH
OH
cyclopentanol
6
Naming Ethers
Write the name of each group attached to the O
 Use alphabetical order
 If the groups are the same, use the prefix “di”

O
H3C
CH3
CH2
H3C
CH2
O
CH2
O
CH3
CH3
ethyl methyl ether
diethyl ether
cyclopropyl methyl ether
7
Solubility
“Like dissolves like” explains solubility
 Alkanes are nonpolar



they are insoluble in water
Ethers are slightly polar
ethers with small carbon chains are water soluble
 ethers with long carbon chains are water insoluble


Alcohols are polar
alcohols with small/medium C chains are soluble
 alcohols with large C chains are water insoluble.

8
Give Name: Solubility
propane: insoluble in water
O
dimethyl ether: soluble in water
O
dibutyl ether: insoluble in water
ethanol: soluble in water
OH
1-hexanol: soluble in water
OH
1-octanol: insoluble in water
OH
9
Aldehyde and Ketone
10
Oxidation Reaction

In one kind of oxidation rxn of alcohols, the carbon
bearing the OH turns into a C=O group
If the C bearing the OH is attached to one other
carbon or less, an aldehyde forms
 If the C bearing the OH is attached to two other
carbons, a ketone forms
 If the C bearing the OH is attached to three other
carbons, no reaction happens.

11
O
[O]
O
H3C
H3C
H
O
[O]
O
CH2
H3C
H
H
aldehyde
C
H3C
H
CH
H
C
H3C
H
O
ketone
[O]
O
aldehyde
C
CH3
H3C
H3C
C
H3C
[O]
O
H
CH3
no reaction
12
Draw the product: aldehyde,
ketone, or NR?
O
OH
ketone
[O]
H
aldehyde
[O]
HO
O
O
OH
[O]
ketone
13
Naming Aldehydes
Name the longest carbon chain containing the
carbonyl (C=O)
 Use the suffix “al”
 Name any substituents by numbering the
O
carbonyl carbon as number 1

H
O
O
C
C
H
H3C
O
H
H
2-methylpropanal
methanal
(formaldehyde)
ethanal
propanal
14
15
Name These
Br
H
H
O
pentanal
Br
O
2,3-dibromobutanal
16
Naming Ketones
Name the longest carbon chain containing the
carbonyl (C=O)
 Use the suffix “one”
 Number the main chain from the end nearest the
carbonyl. Name and number any substituent

H3C
O
O
C
C
CH3
propanone
(acetone)
H3C
O
CH2CH3
butanone
CH3
3-methylbutanone
17
Name These
O
H
O
O
pentanal
2-pentanone
3-pentanone
18
Name These
O
O
O
CH3
Cl
cyclopentanone
Cl
3-heptanone
3,3-dichlorobutanone
19
Properties
Aldehydes and ketones are slightly polar
 They tend to have similar bps to ethers of the
same molar mass
 They tend to have much lower bps than
alcohols, because alcohols are much more polar
 Aldehydes and ketones of 5 C atoms or less are
soluble in water

20
Chemical Tests

In Tollens’ test, an aldehyde is oxidized to a
carboxylic acid. Silver also forms.
CH3CHO + 2 Ag+  2 Ag(s) + CH3COOH
21
22
Chemical Tests

In Benedict’s test, an aldehyde that has an
OH group on the next carbon forms a
carboxylic acid. Red ppt also forms.
RCHO + 2Cu2+  Cu2O(s) + RCOOH
23
24
Isomers
Isomers are compounds with the same
formula, but the atoms are attached
differently
 “Stereoisomers” have the atoms arranged
differently in space--they are related as
mirror images.

25
Chiral Carbons

Chiral carbons are tetrahedral carbons with
four different attachments
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