Problem 89 - A Complete Resource Book in Chemistry for JEE Main

Question

Conversion of acetaldehyde into ethyl acetate in presence of aluminium ethoxide is called (a) Tischenko reaction (b) aldol condensation (c) Benzoin condensation (d) Cope reaction

Step-by-Step Solution

Answer

The reaction is Tischenko reaction (option a).

Step 1: Identify Reactants and Products

The task is to identify the reaction whereby acetaldehyde is converted into ethyl acetate using aluminium ethoxide as a catalyst. Recognize that acetaldehyde is an aldehyde, and ethyl acetate is an ester.

Step 2: Analyze Reaction Type

Notice that the conversion of an aldehyde to an ester through the use of a metal alkoxide is a characteristic of a specific type of organic reaction. Aluminium ethoxide acts similarly to the role of other metal alkoxides in facilitating this transformation.

Step 3: Connection to Named Reactions

Understanding these transformations as a result of specific reaction mechanisms, compare the given named reactions. The transformation from acetaldehyde to ethyl acetate in the presence of aluminium ethoxide is specifically known as the Tischenko reaction.

Key Concepts

Acetaldehyde Conversion

The conversion of acetaldehyde into other compounds is an essential part of organic chemistry, as it involves the transformation of a simple aldehyde into more complex molecules. Acetaldehyde, with its chemical formula \( \text{CH}_3\text{CHO} \), is a key intermediate compound in various organic reactions. This conversion process plays a pivotal role in synthesizing other compounds, such as esters and alcohols, which are important for various industrial applications.

When acetaldehyde interacts with aluminium ethoxide, it undergoes a conversion process typical of the Tischenko reaction. This results in the formation of ethyl acetate, demonstrating the power of acetaldehyde as a valuable building block in chemical synthesis.

• Acetaldehyde is an aldehyde (functional group \(-\text{CHO}\)).
• Highly reactive due to the presence of the carbonyl group \(\text{C}=\text{O}\).
• Serves as a precursor for numerous organic reactions, including the formation of esters.

Ethyl Acetate Formation

Ethyl acetate is an ester that forms through a fascinating class of reactions in organic chemistry, where acids and alcohols react. In the Tischenko reaction, two molecules of acetaldehyde, with the help of aluminium ethoxide, convert into ethyl acetate \((\text{CH}_3\text{COOC}_2\text{H}_5)\).

This process is notable because it doesn't involve external acid or alcohol sources. Instead, the aldehyde itself serves as both donor and acceptor of the alcohol group, facilitated by the catalyst, resulting in the ester link formation. This makes the reaction quite unique and efficient in synthetic terms.

• Ethyl acetate is employed in the production of paints, coatings, and adhesives.
• It acts as a solvent in nail polish removers and glues.
• The reaction showcases the utility of aldehydes beyond their typical uses.

Aluminium Ethoxide

Aluminium ethoxide is a crucial catalyst in the Tischenko reaction, effectively facilitating the conversion of acetaldehyde to ethyl acetate. As a metal alkoxide, it aids in the transformation by influencing the reactivity of the aldehyde. It is a metal-organic compound with the formula \( \text{Al} \left(\text{OC}_2\text{H}_5\right)_3 \), and it plays an instrumental role in many organic synthesis processes.

In the Tischenko reaction, aluminium ethoxide operates by forming an intermediate complex with acetaldehyde. This complex then rearranges, leading to the formation of the ester linkage characteristic of the product, ethyl acetate.

• Serves as a catalyst, accelerating reactions without being consumed.
• Enhances reaction yields, essential in industrial applications.
• Exhibits characteristics common to metal alkoxides, such as promoting nucleophilic attack.