Question

When a mixture of secondary amines is heated with diethyl oxalate, it forms (a) solid oxamic ester (b) liquid oxamic ester (c) form of oxamic ester (d) gaseous oxamic ester

Short answer

The correct answer is (a) solid oxamic ester.

Step-by-step solution

Identify the Chemical Reaction

The problem describes a reaction where secondary amines are heated with diethyl oxalate. This particular reaction is known for producing oxamic esters.

Understand the Nature of Oxamic Esters

Oxamic esters formed in this reaction are typically esters derived from oxamic acid. The consistency of these compounds at room temperature is important for determining their state.

Determine the Physical State of Oxamic Esters

Generally, oxamic esters, which are esters of oxamic acid, are known to be solids at room temperature. This is due to their larger molecular structure and the presence of hydrogen bonding.

Analyze the Options

Given the typical state of oxamic esters, the correct answer should align with the solid nature of these compounds at room temperature. Thus, the correct answer among the options provided should describe the solid state.

Key concepts

Secondary Amines

Secondary amines play an integral role in organic chemistry. They are characterized by the structure R₂NH, where R represents alkyl or aryl groups. These compounds are formed when two of the hydrogen atoms in ammonia, NH₃, are replaced by organic groups.
This structure gives secondary amines their unique properties, such as basicity, and their ability to participate in a variety of reactions, including the one with diethyl oxalate.
In this reaction, secondary amines serve as nucleophiles, meaning they donate a pair of electrons to form a new bond. This aspect is crucial for the formation of oxamic esters, which are further analyzed below.

Diethyl Oxalate

Diethyl oxalate is an ester with the chemical formula C₆H₁₀O₄. It is often used in organic synthesis as an intermediate compound. This molecule is particularly interesting because it contains ester groups that are reactive with amines.
In the reaction with secondary amines, diethyl oxalate acts as an electrophile. This means it accepts a pair of electrons from the amine, initiating the process that leads to the formation of oxamic esters.
Understanding diethyl oxalate's role as an electrophilic agent helps clarify why it reacts readily with secondary amines, facilitating organic chemical transformations.

Oxamic Ester

Oxamic esters are the main product of this specific reaction between secondary amines and diethyl oxalate. An oxamic ester is typically derived from oxamic acid and features the ester functional group in its structure.
The general reaction mechanism involves the substitution of one of the ester groups of diethyl oxalate with the secondary amine. This results in the formation of an oxamic ester.
These compounds are significant in both synthetic and pharmaceutical chemistry, often serving as intermediate products in the preparation of more complex molecules.

Reaction Products

The reaction between a mixture of secondary amines and diethyl oxalate primarily yields oxamic esters. Beyond this, the reaction conditions may also produce other by-products, although these are typically minimal.
It is essential to ensure that the reaction environment is controlled to maximize the formation of oxamic esters while minimizing unwanted side reactions.
Understanding the reaction products in this context helps chemists design experiments that efficiently produce desired compounds while keeping impurities at bay.

Physical State of Compounds

The physical state of a compound can tell us a lot about its structure and bonding. Oxamic esters formed from secondary amines and diethyl oxalate are typically solids at room temperature. This is largely due to the molecular size and the potential for hydrogen bonding between molecules.
Solid-state compounds like oxamic esters have ordered structures, which contribute to their stability and definitive melting points.
Grasping the importance of the physical state helps in practical applications, such as storage and handling, of these compounds.