Cannizzaro reaction is not given by Acetaldehyde -CH3CHO.
Compounds that lack the presence of α−H undergo a Cannizzaro reaction. The compounds that have an α−H show an aldol reaction.
When treated with an aqueous base CH3CHO does not undergo a Cannizzaro reaction because it has α−H and in the presence of an aqueous base, it undergoes aldol condensation.
Benzaldehyde has a benzyl group on α-C. Therefore, it is not the correct answer.
In trimethyl acetaldehyde, there are 3-CH3 groups attached to the α C. So, it will give Cannizzaro reaction.
In formaldehyde, there is no α-C, hence it is the wrong answer.
In the case of 2,2,2-dimethyl propanal, it contains three methyl groups attached to the carbonyl carbon. Therefore, this is also not the correct answer.
1. The Cannizzaro reaction finds utility in pharmaceutical synthesis, where it aids in creating essential compounds used in various medications. 2. This reaction is used in chemical industries to produce key intermediates and raw materials required for the synthesis of various chemicals and products. 3. The Cannizzaro reaction plays a role in the production of fine chemicals used in specialty industries such as cosmetics, fragrances, and flavorings. 4. It is utilized for the purification of alcohols, separating mixtures and obtaining purified products. 5. The reaction serves as a valuable tool in organic synthesis, enabling the conversion of aldehydes into corresponding alcohols or acids, depending on the reaction conditions.
Question can also be asked as
Which aldehyde does not give Cannizzaro reaction?
What is the reason why CH3CHO does not give Cannizzaro reaction?
What is the difference between Cannizzaro reaction and Aldol condensation?
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The correct answer is Option B) \(CH_3CHO\)
The Cannizzaro reaction involves the simultaneous oxidation and reduction of an aldehyde compound. While this reaction is known to occur for many aldehydes, it is important to note that CH3CHO (acetaldehyde) does not undergo the Cannizzaro reaction.
Understanding the Cannizzaro Reaction
The Cannizzaro reaction is a redox reaction that involves the self-disproportionation of aldehydes. One molecule of an aldehyde is oxidized to a carboxylic acid, while another molecule is reduced to an alcohol.
The Cannizzaro reaction proceeds through a concerted process involving a hydride transfer.
A strong base, typically an alkali metal hydroxide, acts as both the reactant and the catalyst.
The Cannizzaro reaction is an essential tool in organic synthesis, allowing the conversion of aldehydes into valuable carboxylic acids and alcohols.
Exclusion of CH3CHO in the Cannizzaro Reaction
1. Lack of α-Hydrogen: The Cannizzaro reaction requires the presence of α-hydrogen atoms in the aldehyde compound. CH3CHO (acetaldehyde) lacks α-hydrogens, as it has only one alkyl group attached to the carbonyl carbon. Without α-hydrogens, the necessary hydride transfer cannot occur.
2. Stabilization of Intermediates: The α-hydrogen atoms play a crucial role in stabilizing the reaction intermediates. In the Cannizzaro reaction, the hydride transfer generates an anionic intermediate, which is stabilized by the presence of α-hydrogens. Without α-hydrogens, the reaction pathway for CH3CHO is energetically unfavourable.
3. Different Reactivity: CH3CHO exhibits different reactivity compared to other aldehydes. Due to its unique electronic and steric properties, acetaldehyde tends to undergo alternative reactions, such as Aldol condensation, rather than the Cannizzaro reaction.
Aldehydes, Ketones, and Carboxylic Acids are carbonyl compounds that contain a carbon-oxygen double bond. These organic compounds are very important in the field of organic chemistry and also have many industrial applications.
Aldehydes:
Aldehydes are organic compounds that have the functional group -CHO.
Preparation of Aldehydes
Acid chlorides are reduced to aldehydes with hydrogen in the presence of palladium catalyst spread on barium sulfate.
Ketones:
Ketones are organic compounds that have the functional group C=O and the structure R-(C=O)-R’.
Preparation of Ketones
Acid chlorides on reaction with dialkyl cadmium produce ketones. Dialkyl cadmium themselves are prepared from Grignard reagents.
Carboxylic Acid:
Carboxylic acids are organic compounds that contain a (C=O)OH group attached to an R group (where R refers to the remaining part of the molecule).
Preparation of Carboxylic Acids
Primary alcohols are readily oxidized to carboxylic acids with common oxidizing agents such as potassium permanganate in neutral acidic or alkaline media or by potassium dichromate and chromium trioxide in acidic media.
