Question

What is a carboxylic ester? How are they made, and how are they named?

Answer 1

A carboxylic ester is the condensation product of a carboxylic acid and an alcohol....so here the alcohol, and it does not have to be ethanol, is a reactant.

Explanation:

And we name them say alkyl alkanoate....where the alkyl is the parent alcohol, and alkanoate is from the parent carboxylic acid.

Were we to make the ethyl ester of acetic acid, we would mix ethyl alcohol with acetic acid and heat them up....to get the condensation reaction to go....

`"H"_3"CCH"_2"OH" + "HO(O=)CCH"_3 stackrel(Delta,H^+)rarr"H"_3"CCH"_2"O(O=)CCH"_3 +"H"_2"O"`

Alternatively, we could make the acid halide from heating the acid at reflux in thionyl chloride, and then treating this with ethyl alcohol in the presence of 1 equiv of base...

`"H"_3"CCO"_2"H" + "SOCl"_2 stackrelDeltararr"H"_3"CC(=O)Cl" + "SO"_2(g)uarr+ "HCl"uarr`

The acid halide could then be treated with ethanol with 1 equiv of base, to make the ester efficiently...

`"H"_3"CC(=O)Cl" +"HOR" stackrel("Et"_3"N")rarr"H"_3"CC(=O)OR"+"Et"_3"N"*"HCl"darr`