Question

Give reasons for the following.
Acetylation of aniline reduces its activation effect.

Answer 1

Hint: Acetylation is a chemical reaction that is called ethanoylation in the IUPAC nomenclature. It explains a reaction that includes an introduction of an acetyl functional group into a chemical compound. The opposite chemical reaction for acetylation is called deacetylation which means it is the removal of the acetyl group from a chemical compound.

Complete step by step answer:
The activation effect can be defined as the increase in the reactivity of a compound by the increase in the availability of the number of electrons in the compound which are readily transferred in the solution and there occurs a progress in the reaction. The electron withdrawing groups decrease the activation effect of the compounds whereas the electron donating groups increase the activation effect by increasing the availability of electrons in the compound.
The reaction that takes place in the acetylation of aniline is as follows:
\[Ph - N{H_2}\xrightarrow[{Pyridine}]{{RCOCl}}Ph - NHCOR\]
In the above reaction, aniline is a moderate base as it is an electron rich compound and acts as a good nucleophile. The electron cloud of aniline remains stable unless it is being reacted with some acetyl halide to produce an acetic anhydride. The acetyl group that later gets attached with aniline deactivates the aniline because of its electron withdrawing tendency. Thus, we can say that acetylation of aniline reduces its activation effect.


Note:
Acetylation is the reaction which involves the replacement of the hydrogen atom of a hydroxyl with an acetyl group (\[C{H_3}CO\] ) yields a specific ester which, in this case, is known as the acetate. Acetic anhydride is commonly used as an acetylating agent reacting with free hydroxyl groups. For example, it is used in the synthesis of aspirin, heroin, etc.