Question

what is cannizaro reaction??..​

Answer 1

Answer:

The Cannizzaro reaction, named after its discoverer Stanislao Cannizzaro, is a chemical reaction that involves the base-induced disproportionation of two molecules of a non-enolizable aldehyde to give a primary alcohol and a carboxylic acid.

Mechanism of Cannizzaro Reaction :-

• 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 then picks up a proton from water to provide the alcohol final product, while the caboxylate is converted to the carboxylic acid product after acid work-up

Answer 2

Answer: Cannizaro reaction is a reaction in which aldehyde whose alpha hydrogen is absent reacts with conc. alkali and form salt and alcohol.

Conditions for Cannizaro reaction:-

a. Conc. Alkali must be present.

b. Alpha hydrogen must be absent.

* Reaction in which the alpha hydrogen is absent:-

       RCHO + RCHO (+ conc. NaOH) ⇒ R-COONa + R-CH₂-OH

You can put benzene in place of R in the above reaction which will be an example of Cannizaro Reaction.*