Nomenclature
What about the naming of these compounds? Ethers are usually referred to using their
common names.
As you can see in the following structural formulas, an ether has two alkyl groups
attached to an oxygen atom. To name an ether, all you have to do is name the two
alkyl groups and then follow those names by the word ether.
Examples
| In this example (also shown in Example 21-a in your workbook), one of the
alkyl groups attached to the oxygen is a methyl group; and the other group is an ethyl
group. Thus, we have methyl ethyl ether.
(Or, ethyl methyl ether. You do not have to be terribly worried about
sticking to alphabetical order when naming ethers.) When naming ethers the name of
each alkyl group is treated as a separate word. So methyl ethyl ether is three words. |
H H H
| | |
H-C-O-C-C-H
| | |
H H H
methyl ethyl ether |
|
| In this example (also shown in Example 21-b) both of the alkyl groups are
the same. When this happens, two options are available to you. This ether is composed of
two ethyl groups attached to an oxygen. So this could be called diethyl ether
to indicate the presence of two ethyl groups. Or it can simply be referred to as ethyl
ether. The assumption here is that whoever is reading the name knows enough about
ethers to know that there are two groups attached to the oxygen. If only one kind of alkyl
group is indicated, then both of the alkyl groups attached to the oxygen must be the same
alkyl group. |
H H H H
| | | |
H-C-C-O-C-C-H
| | | |
H H H H
diethyl ether or ethyl ether
(commonly known simply as "ether") |
|
Diethyl ether is usually the ether that is referred to when someone just says
"ether" without indicating what alkyl groups are attached. It used to be
commonly used as an anesthetic. It is also quite frequently used in chemistry as a
solvent. This particular compound is very dangerous because it is very volatile and very
flammable. So the danger of explosion is very high when ether is being handled.
It is also for that reason that when you are in the lab you will work with some models
of ethers instead of with the real thing. Take time now to make models of the two ethers
shown above (and in Example 21) and compare them with the space filling models on display
in the lab on the demonstration table.
Practice
Now try your hand at drawing the structural formulas for ethers when given the name or
coming up with the name when given the structural formula. See what you can do with the
compounds below (which are also shown in Exercise 22 in your workbook with one variation).
Please do that now and then check your answers below before you continue with the lesson.
isopropyl butyl ether
|
methyl ether
|
H H H H
| | | |
H-C-C-C-O-C-H
| | | |
H H H H |
H H H H H
| | | | |
H-C-C-C-O-C-C-H
| | | | |
H H H H H |
Answers
isopropyl butyl ether
|
CH3
H H H H
| | | | |
H-C-O-C-C-C-C-H
| | | | |
CH3 H H H H |
methyl ether
|
H H
| |
H-C-O-C-H
| |
H H |
H H H H
| | | |
H-C-C-C-O-C-H
| | | |
H H H H |
methyl propyl ether |
H H H H H
| | | | |
H-C-C-C-O-C-C-H
| | | | |
H H H H H |
ethyl propyl ether |
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E-mail instructor:
Sue Eggling
Clackamas Community College
©2001, 2003 Clackamas Community College, Hal Bender
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