Esterification of Ethanoic Acid
Esterification of Ethanoyl Chloride
Formation of an ester from an Acyl Chloride
Above shows the equation for the formation of an ester from ethanoyl chloride, the only difference from that of the formation from ethanoic acid is that HCl is given off instead of water, the reasons for this are simple - in the structure of ethanoyl chloride (below) it simply has a Cl atom instead of the -OH in ethanoic acid
Although esterification with an acid catalyst from an alcohol and a carboxylic acid is a perfectly good method of achieving the product, the use of an Ethanoyl Chloride is a much more efficient way of doing this as the -COCl group is much more reactive, this is because the chlorine molecule is a much better leaving group due to its low pKa.
Mechanism for formation of an ester
The diagram above shows the curly-arrow mechanism for the synthesis of an ester from ethanol and ethanoyl chloride (curly-arrows simply show the movement of electrons, for example when the lone pair on the hydroxide removes the acidic hydrogen). The mechanism is clearly very simlar to that for the formation of an ester from a carboxcylic acid, and indeed ethanoyl chloride is a dirivitive of a carboxylic acid, the only difference being that the Cl atom is a much leaving group.