Question

Explain Aldol condensation with one example.

Answer 1

Hint: Aldol condensation is an organic reaction. The final product of the Aldol condensation reaction is a β-hydroxy aldehyde or β-hydroxy ketone, respectively. β-hydroxy aldehyde is commonly known as aldol, and the β-hydroxy ketone is commonly known as ketol.


Step by step answer: In an aldol condensation reaction, the aldehydes and ketones having at least one α-hydrogen participate in the presence of a catalyst. The catalyst in the Aldol condensation reaction is the dilute alkali. The example of aldol condensation in which the ethanal that is one of the aldehyde in the presence of dilute alkali acid that is NaOH gives a aldol product that is $$3-\mathrm{h}\mathrm{y}\mathrm{d}\mathrm{r}\mathrm{o}\mathrm{x}\mathrm{y}\mathrm{b}\mathrm{u}\mathrm{t}\mathrm{a}\mathrm{n}\mathrm{a}\mathrm{l}$$. The chemical reaction is shown below.

$$\mathrm{C}{\mathrm{H}}_3-\mathrm{C}\mathrm{H}\mathrm{O}+\mathrm{C}{\mathrm{H}}_3-\mathrm{C}\mathrm{H}\mathrm{O}\to \mathrm{C}{\mathrm{H}}_3-\mathrm{C}\mathrm{H}(\mathrm{O}\mathrm{H})-\mathrm{C}{\mathrm{H}}_2-\mathrm{C}\mathrm{H}\mathrm{O}\to \mathrm{C}{\mathrm{H}}_3-\mathrm{C}\mathrm{H}=\mathrm{C}\mathrm{H}-\mathrm{C}\mathrm{H}\mathrm{O}+{\mathrm{H}}_2\mathrm{O}$$

In an aldol condensation reaction, both the aldol and ketol formed readily lose water and the aldol condensation product, i.e., α, β-unsaturated carbonyl compounds are formed. This reaction's name has been derived from the functional groups, namely aldehyde and alcohol present in the reaction products.

Hence, the Aldol condensation reaction is an organic reaction in which a carbonyl compound reacts with enolate ion and leads to the formation of the β-hydroxy aldehyde or β-hydroxy ketone. Thus, aldol condensation reaction occurs when aldehydes or ketones have at least one α-hydrogen reaction in the presence of a dilute alkali, e.g., NaOH, to produce β-hydroxy aldehyde or β-hydroxy ketone.


Note: But when aldol condensation is carried out between two different ketones or aldehydes, this reaction is termed as the cross aldol condensation reaction