Base catalysed aldol condensation occurs with :a)Benzaldehydeb)Ethanalc)2, 2-Dimethylpropanald)FormaldehydeCorrect answer is option 'B'. Can you explain this answer?

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Answer

Ethanal means acetaldehyde response in aldol condensation reaction..because it has alpha-hydrogen...only that compound response in aldol condensation reaction whose has a alpha hydrogen like acetaldehyde, acetone etc..acetaldehyde produces 2-hydroxy butanal in aldol condensation reaction. so correct option is ACETALDEHYDE

Answer

Answer

Aldol condensation:
Aldol condensation is a reaction in which an aldehyde or ketone reacts with another aldehyde or ketone to form a β-hydroxyaldehyde or β-hydroxyketone. The reaction involves the formation of an enolate intermediate, followed by nucleophilic attack and dehydration.

Base-catalysed aldol condensation:
In base-catalysed aldol condensation, a base is used to deprotonate the α-carbon of the aldehyde or ketone, forming an enolate ion. The enolate ion then attacks the carbonyl carbon of another aldehyde or ketone, forming a new carbon-carbon bond. The resulting β-hydroxyaldehyde or β-hydroxyketone can undergo dehydration to form an α,β-unsaturated aldehyde or ketone.

Choice of base:
The choice of base in base-catalysed aldol condensation is crucial as it determines the rate and selectivity of the reaction. A strong base is required to deprotonate the α-carbon and form the enolate ion. In this case, the base-catalysed aldol condensation occurs with ethanol (option B) as the base.

Explanation:
Ethanol can act as a base and deprotonate the α-carbon of the aldehyde or ketone. The resulting enolate ion can then attack the carbonyl carbon of another aldehyde or ketone, leading to the formation of a new carbon-carbon bond.

The choice of ethanol as the base in this reaction is suitable because it is a relatively weak base compared to other options such as benzaldehyde, 2,2-dimethylpropanal, or formaldehyde. A stronger base might lead to over-deprotonation and the formation of an enolate ion that is too nucleophilic, resulting in unwanted side reactions.

Ethanol also has a higher boiling point compared to other options, which allows for better control of the reaction temperature. The reaction is typically carried out at elevated temperatures to favor the formation of the desired aldol product.

Overall, the choice of ethanol as the base in base-catalysed aldol condensation is appropriate due to its moderate basicity and higher boiling point, which allow for efficient and selective formation of the desired aldol product.

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