(i) Acetylation : When active hydrogen atom of alcohol, phenol (or) an amine is replaced by acetyl (CH3CO–) group to form corresponding ester (or) amide, the reaction is known as acetylation.
→ Reagents used are acid chloride (or) acid anhydride in presence of a base like pyridine (or) dimethylaniline.
For example :
4 – methoxy acetophenone (major)
(ii) Cannizaro reaction : On treating with concentrated alkali, aldehydes which do not have any α – hydrogen atom, undergo self oxidation and reduction (disproportionation) reaction. This reaction is called cannizaro reaction.
→ As a result, one molecule of aldehyde is reduced to alcohol while another is oxidised to carboxylic acid salt.
For example :
