Eduprobe
Question:
The correct statement about the synthesis of erythritol (C(CH₂OH)₄) used in the preparation of PETN is:
The synthesis requires three aldol condensations and one Cannizzaro reaction
Alpha hydrogens of ethanol and methanol are involved in this reaction
The synthesis requires four aldol condensations between methanol and ethanol
The synthesis requires two aldol condensations and two Cannizzaro reactions
Solution:
The correct answer is A. The synthesis requires three aldol condensations and one Cannizzaro reaction.
Erythritol is a four-carbon sugar alcohol. Its synthesis doesn't directly involve ethanol and methanol. The synthesis typically starts with formaldehyde, which undergoes a series of aldol condensations and a Cannizzaro reaction to form erythritol.
Aldol Condensation: This reaction involves the nucleophilic addition of an enolate ion to an aldehyde or ketone, followed by dehydration to form an α,β-unsaturated carbonyl compound. In the synthesis of erythritol, multiple aldol condensations build the carbon chain.
Cannizzaro Reaction: This is a redox disproportionation reaction involving two molecules of an aldehyde without α-hydrogens, producing one carboxylic acid and one alcohol. This reaction plays a role in the final steps of erythritol synthesis.
Therefore, the synthesis of erythritol involves several steps which includes three aldol condensations and one Cannizzaro reaction to form the final product. Options B, C, and D are incorrect due to the inaccurate number of aldol condensations and Cannizzaro reactions involved in the actual synthesis pathway.