Which one of the following choices describes most accurately the actual, internal reaction temperature (in other words, the temperature of the reaction mixture inside the reaction vial) for the Fischer esterification experiment of 1-butanol with acetic acid to form n-butyl acetate? Select one, and explain your answer.

a) Sand bath temperature (160-180 °C)
b) Boiling point of 1-butanol (116-118 °C)
c) Boiling point of the reaction mixture (reflux temperature)
d) Boiling point of acetic acid (117 °C)
e) Boiling point of n-butyl acetate (124-126 °C)

c) Boiling point of the reaction mixture (reflux temperature)

Explanation:

Hello,

At first, it is important to remember that esterification is an organic chemical reaction related with the neutralization of organic acids and alcohols to form esters, in this case from 1-butanol and acetic acid to n-butyl acetate as shown below:

It is shown that is a reaction which equilibrium condition is present since the n-butyl acetate is likely to come back to the acetic acid and the 1-butanol. Moreover, it is necessary to catalyze esterification with sulfuric acid and including constant heating and stirring, nonetheless, such heating induces boiling of the reacting mixture containing the acetic acid and the 1-butanol which are likely to boil. Therefore, reflux must be implemented as shown on the attached picture to prevent reactant lost which shift the reaction leftwards, diminishing n-butyl acetate yield, thus, the most accurately way to describe the actual temperature is c) boiling point of the reaction mixture (reflux temperature) since acetic acid and 1-butanol have a composition which modifies their boiling point into an only one that is the mixture's boiling point which is also related with the temperature at which the reflux is performed.

Best regards.