Question

Explain the following name reaction with a suitable chemical reaction.
Cannizaro’s reaction.

Answer 1

Hint: This reaction is named after its discoverer Stanislao Cannizzaro. You should know that the products formed from this reaction are primary alcohol and a carboxylic acid. Now try solving the question.

Complete step by step answer:
> Let us know this reaction in detail.
The Cannizzaro reaction is a redox reaction in which two molecules of an aldehyde are reacted to produce a primary alcohol and a carboxylic acid using a hydroxide base.
> Let us see the mechanism of Cannizzaro reaction.
- You should know that the reaction begins with hydroxide attack on the carbonyl carbon followed by deprotonation to give a dianion. This unstable intermediate releases a hydride anion which attacks another molecule of aldehyde.
- In this process the dianion converts to a carboxylate anion and the aldehyde to an alkoxide.
The alkoxide in the reaction then picks up a proton from water to provide the alcohol as the final product, while the carboxylate is converted to the carboxylic acid product after acid work-up.
Let us understand better with the help of the reaction.

Example of Cannizzaro reaction , when formaldehyde is disproportionated to formic acid and methyl alcohol in strong alkali.
$HCHO\xrightarrow [ NaOH ]{ } HCO{ O }^{ - }{ Na }^{ + }+{ CH }_{ 3 }OH$

Note: The variations of the reaction improve the yield of the desired product. The Cannizzaro reaction can be used to influence a disproportionation of two molecules of a non-enolizable aldehyde to give a primary alcohol and a carboxylic acid.