Aldol condensation is a self condensation reaction of aldehydes and ketones having ? - hydrogen (hudrogen attached to the carbon atom adjacent to the carbonyl group) in the presence of dilute alkali to form ? - hydroxy aldehyde or ? - hydroxy ketone . The products are commonly called aldols derived from the coombination of words aldehyde and alcohol because products have both these functional group.
In the presence of NaOH
2 CH3CHO ? CH3CHOHCH2CHO
1.OH- abstracts h+ fromone acetaldehyde molecule to form resonance stabilised enolate ion
HO- + H-CH2CHO ? -CH2CHO
2. Enolate ion being a nucleophile attacks carbonyl carbon of other acetaldehyde molecule
CH3CHO + -CH2CHO ? CH3CHO-CH2CHO
acetaldehyde Enolate ion Anion
3. The anion formed abstacts proton from water to form aldol.
CH3CHO-CH2CHO + H2O ? CH3CHOHCH2CHO