This conducted experiment involved the preparation of 1-butyl ethanoate, an ester. Ester is an important functional group that can be synthesized by several methods. Firstly, reaction of a carboxylic acid and an alcohol through condensation reaction to form an ester with two conditions: extended heating under reflux and in the presence of catalyst such as p-toluene sulfonic acid, concentrated sulfuric acid, hydrochloric acid, or the acid form of an ion exchange resin. This procedure is generally known as Fischer ester synthesis. It is reversible but proceeds slowly and therefore a catalyst should be used. With the presence of catalyst, the reaction will attain equilibrium more rapidly. However, the presence of catalyst will not affect the amount of products formed at equilibrium. This procedure is generally known as Fischer ester synthesis. The mechanism of this reaction includes initial protonation of the carboxyl group. Then, attack by the nucleophilic hydroxyl. Next, transference of proton in the molecule. Afterwards, loss of water followed by loss of the catalysing proton and an ester is obtained. Secondly, reaction of an …show more content…
Because the procedure to synthesis ester can carry out easily, flavour chemist use ester frequently to reproduce or enhance natural flavours. Nevertheless, esters are always used in the food and perfume industry for fragrances and artificial flavors, they are rarely used as perfume for body as they are not highly stable and can be hydrolysed back to alcohols and carboxylic acid when exposed to perspiration. As esterification is a reversible reaction, the addition of heat, water and acid favours hydrolysis. And, unfortunately, many simple carboxylic acids have a quite sharp and unpleasant odour. Besides, some ester also