Question

Which of the following reaction is given by a primary amine? (1) Carbyl amine reaction (2) Mustard oil reaction (3) Reaction with ceric ammonium nitrate (4) Diazotization (a) 3 and 4 (b) 1,2 and 3 (c) 1,2 and 4 (d) 2 and 3

Short answer

Option (c) 1, 2, and 4 are the reactions given by a primary amine.

Step-by-step solution

Identify Reactions of Primary Amine

Primary amines are known to participate in reactions that are characteristic to their structure. They are known for reactions like carbyl amine reaction and diazotization, which specifically involve primary amines.

Analyze Option 1: Carbyl Amine Reaction

The carbyl amine reaction is a chemical test for primary amines. It involves the reaction of primary amines with chloroform and alcoholic potassium hydroxide to form isocyanides, which have a distinctive foul smell. This reaction is characteristic of primary amines.

Analyze Option 2: Mustard Oil Reaction

The mustard oil reaction also involves primary amines. In this reaction, primary amines react with carbon disulfide and an excess of lead nitrate to form isothiocyanates or 'mustard oil'. This test is particularly used for the detection of primary amines.

Analyze Option 3: Reaction with Ceric Ammonium Nitrate

Ceric ammonium nitrate is used as a qualitative test for alcohols, rather than amines. Therefore, primary amines generally do not show characteristic reactions with ceric ammonium nitrate.

Analyze Option 4: Diazotization

Diazotization refers to the conversion of primary aromatic amines into diazonium salts by treatment with nitrous acid. This reaction is unique to primary amines, particularly aromatic ones.

Evaluate Given Options

Having identified which reactions involve primary amines: carbyl amine reaction, mustard oil reaction, and diazotization, we see that options 1, 2, and 4 correspond to reactions involving primary amines.

Select the Correct Option

Based on the analysis, option (c) 1, 2, and 4 are the reactions given by primary amines.

Key concepts

Carbyl Amine Reaction

The Carbyl Amine Reaction is a well-known chemical test specifically for primary amines. This reaction involves the interaction between a primary amine, chloroform, and alcoholic potassium hydroxide. When these compounds are combined, they form an isocyanide compound. A distinct feature of this reaction is the production of a very characteristic foul smell, often likened to the smell of burnt rubber or rotting fish. This odor provides a strong indication of the presence of a primary amine.

This reaction is particularly useful because it only works with primary amines and does not occur with secondary or tertiary amines. The specificity of the Carbyl Amine Reaction makes it an essential tool for chemists to detect primary amines in a mixture.

• Formed Isocyanides have a foul odor.
• Uses chloroform and alcoholic KOH.
• Only primary amines participate.

Mustard Oil Reaction

The Mustard Oil Reaction is another test for primary amines, which is known for its unique process and result. In this reaction, a primary amine reacts with carbon disulfide (S_2) in the presence of an excess of lead nitrate, leading to the formation of isothiocyanates, commonly known as 'mustard oils'.

Just like the Carbyl Amine Reaction, the Mustard Oil Reaction helps in the detection of primary amines due to its selectivity. The isothiocyanates formed resemble the pungent smell of mustard oil, giving this reaction its name.

Chemists often rely on this reaction not only for qualitative analysis but also as a precursor step in some synthetic processes involving isothiocyanates. Here are some key points regarding this reaction:

• Involves Carbon Disulfide and Lead Nitrate.
• Only primary amines form isothiocyanates.
• Results in the formation of 'mustard oil'.

Diazotization

Diazotization is a fascinating reaction primarily associated with primary aromatic amines. During this process, nitrous acid is used to convert these amines into diazonium salts. The mechanism involves the formation of an intermediate via the initial reaction with nitrous acid, followed by further transformation into a stable diazonium ion.

The reaction is especially significant because these diazonium salts are versatile intermediates in organic synthesis. They can participate in various chemical reactions such as azo coupling or can be used to form other functional groups.

Understanding diazotization is crucial for chemists dealing with dyes and pigments, as azo compounds derived from diazonium salts are frequently used in these industries. Some important aspects to note are:

• Specific to primary aromatic amines.
• Uses nitrous acid to form diazonium salts.
• Diazonium salts are key intermediates in synthesis.

Ceric Ammonium Nitrate Test

The Ceric Ammonium Nitrate Test is primarily used to detect alcohols, rather than amines. When it comes to primary amines, this test does not provide significant results. The reaction with ceric ammonium nitrate is significant for alcohols due to the formation of a red complex with various colors indicating specific types of alcohols.

Given that primary amines do not engage in the same reactions with ceric ammonium nitrate, it falls outside the scope of primary amine diagnostic tests. Therefore, rhe role of ceric ammonium nitrate in the context of primary amines is usually negligible.

When studying the reactions involving ceric ammonium nitrate, it’s essential to remember it is a qualitative indicator, largely for alcohols and not for amines. Here’s what to keep in mind:

• Targets alcohols, not amines.
• Forms colored complexes with alcohols.
• Not useful for primary amine detection.