Consider the following reaction:
Ethanol plus butanoic acid react to produce blank and H2O. What ester is produced from this
reaction? (A) Ethyl butanoate, (B) ethyl
propanoate, (C) propyl butanoate, (D) methyl butanoate, or (E) butyl ethanoate.
The names of esters have two parts
which come from the esters’ parent molecules, which are the species used to make the
ester. Alcohols and carboxylic acids are
common parent molecules for esters. So to find the first part of the
ester’s name, you take the first part of the parent alcohol’s name and add the
suffix -yl. And to find the second part of the
ester’s name, you take the first part of the parent carboxylic acid’s name and add
the suffix -oate.
Now, we know how to name an
ester. Let’s look at the reaction given in
the question. We can see that ethanol — which has
the ending -ol, so is an alcohol — and butanoic acid — which has the ending -oic
acid, so is a carboxylic acid — react to produce an unknown compound and water.
The question tells us that the
unknown compound is an ester. So we just need to work out its
name from the name of its parent molecules. The first part of an ester’s name
comes from the first part of its parent alcohol’s name, which we know to be
ethanol. We take the first part of the name,
which is F, and add the suffix -yl to give us the name ethyl. And to find the second part of the
ester’s name, we take the first part of the parent carboxylic acid’s name which we
know to be butanoic acid. The first part of this name is
butan-, and then we need to add the suffix -oate, giving us the name butanoate.
Therefore, the name of the ester
produced from the reaction of ethanol and butanoic acid is (A) ethyl butanoate.