2,4-dinitrophenylhydrazone

Definition

2,4-dinitrophenylhydrazone is a derivative compound formed by the reaction of 2,4-dinitrophenylhydrazine with a carbonyl-containing compound, such as an aldehyde or ketone. It is a useful tool for the identification and characterization of carbonyl compounds in organic chemistry.

5 Must Know Facts For Your Next Test

1. 2,4-dinitrophenylhydrazone is a yellow-orange crystalline solid that is commonly used to identify and characterize carbonyl compounds.
2. The reaction between 2,4-dinitrophenylhydrazine and a carbonyl compound is a nucleophilic addition reaction, where the hydrazine acts as the nucleophile.
3. The formation of 2,4-dinitrophenylhydrazone is a key step in the Brady's test, a qualitative test used to detect the presence of carbonyl compounds.
4. The distinct color and precipitate formation of the 2,4-dinitrophenylhydrazone derivative allows for the identification of the original carbonyl compound.
5. The 2,4-dinitrophenylhydrazone derivative can be used to determine the molecular weight and structure of the carbonyl compound through further analysis.

Review Questions

• Explain the reaction mechanism for the formation of 2,4-dinitrophenylhydrazone from a carbonyl compound.
  • The formation of 2,4-dinitrophenylhydrazone involves a nucleophilic addition reaction between the 2,4-dinitrophenylhydrazine and a carbonyl compound, such as an aldehyde or ketone. The nucleophilic hydrazine group attacks the electrophilic carbonyl carbon, forming a tetrahedral intermediate. This intermediate then collapses, eliminating water and forming the planar 2,4-dinitrophenylhydrazone product. The presence of the two nitro groups on the phenyl ring increases the reactivity of the hydrazine, making it a stronger nucleophile.
• Describe the key features of 2,4-dinitrophenylhydrazone that make it a useful tool for the identification of carbonyl compounds.
  • The 2,4-dinitrophenylhydrazone derivative has several properties that make it valuable for the identification of carbonyl compounds. Firstly, the distinct yellow-orange color of the 2,4-dinitrophenylhydrazone allows for easy visual detection and identification of the carbonyl compound. Secondly, the 2,4-dinitrophenylhydrazone is a crystalline solid, which can be isolated and further analyzed to determine the molecular weight and structure of the original carbonyl compound. Additionally, the 2,4-dinitrophenylhydrazone derivative is relatively stable, making it suitable for storage and analysis.
• Evaluate the importance of the 2,4-dinitrophenylhydrazone reaction in the context of nucleophilic addition reactions and the characterization of carbonyl compounds.
  • The 2,4-dinitrophenylhydrazone reaction is a crucial tool in organic chemistry for the identification and characterization of carbonyl compounds. As a nucleophilic addition reaction, it demonstrates the reactivity of the hydrazine group towards electrophilic carbonyl carbons, a fundamental concept in understanding the reactivity of carbonyl compounds. The distinct color and precipitate formation of the 2,4-dinitrophenylhydrazone derivative allows for the rapid and unambiguous detection of the original carbonyl compound, making it a valuable qualitative test. Furthermore, the ability to isolate and analyze the 2,4-dinitrophenylhydrazone provides important structural information about the carbonyl compound, enabling its identification and characterization. Overall, the 2,4-dinitrophenylhydrazone reaction is an essential technique in the study of carbonyl chemistry and the identification of organic compounds.

Related terms

Nucleophilic Addition:

A reaction in which a nucleophile adds to an electrophilic carbon, typically a carbonyl carbon, to form a new covalent bond.

Imine Formation:

The reaction between a primary amine and a carbonyl compound to form an imine, a C=N double bond.

Enamine Formation:

The reaction between a secondary amine and a carbonyl compound to form an enamine, a C=C-N functional group.