What are Anilines?

Have you ever questioned yourself why your jeans’ is blue? Yes! It is because the chemical aniline, employed as a coloring agent in the textile industry, is likely responsible for this color. Aniline acts as a representative of N-containing aromatic compounds and is mostly utilized as a chemical intermediary in manufacturing dyes, insecticides, polymers, and medicines.

Aniline dye was first manufactured in 1826, wherein indigo underwent a destructive distillation. Its name is derived from the scientific name of the plant Indigofera anil (Indigofera suffruticosa), which yields indigo. The chemical formula of aniline is C₆H₅NH₂ . Commercially, aniline is produced through the catalytic hydrogenation of nitrobenzene or the reaction of chlorobenzene with ammonia. Iron borings dissolved in aqueous acid can also be used for nitrobenzene reduction.

What is Aniline?

Aniline is an aromatic initial amine. Aniline belongs to nitrogen-altered organic substances. These substances are classified as aromatic amines and are known to be very harmful to human health. These are used in various industrial applications and are known to have all the characteristics of an aromatic chemical.

Aniline Formula: Chemical Formula

 

 

The aniline formula is C₆H₅NH_2.

Aniline Molar Mass: Molecular Weight

The aniline molar mass is 93.13 g/mol.

Aniline Properties

Physical Properties

• Aniline has a thick yellow to brownish liquid with a stinky, fishy odour. It has a melting point of -6 degrees Celsius and a boiling point of 184 degrees Celsius.
• The high aniline point reflects its high paraffinic and flammability.
• Aniline has a strong smell.
• Aniline can also be classified as a polar compound. 
• Aniline’s hydrogen bonds are weaker than phenol’s hydrogen bonds.
• Aniline can form hydrogen bonds with water. However, aniline has limited solubility because of the big phenyl group.
• Ammonia is more basic than aniline. At the same time, aniline is more basic than amides.
• Aniline emits nitrogen oxides, which harm the environment and the human body when ingested through the atmosphere or absorbed by the skin.

Chemical Properties

• Highly combustible 
• Becomes darker when exposed to air and lighting. 
• The chemical breaks down when heated above 190°C or burned, releasing flammable vapours and toxic and corrosive gases (ammonia, carbon monoxide and nitrogen oxides).
• Aniline dye is a weak base.  
• It reacts aggressively with acids, strong oxidants, acetic anhydride, Chlor melamine monomers, epichlorohydrin, and beta-propiolactone, generating a fire risk and explosion. 
• It produces dangerous hydrogen gas when it reacts with metals like sodium, potassium, and calcium. 
• It is highly reactive with copper alloys.

Aniline Reactions

Let’s examine a few reactions of anilines and their derivatives:

Oxidation Reaction: Carbon-nitrogen bonds are frequently formed during the oxidation reactions of aniline compounds.

Basicity: Anilines are less powerful bases forming anilinium ions when interacting with stronger acids.

Acylation: Anilines react quickly with carboxylic acids and produce amide during the acylation reaction.

 

 

Wohl-Aue Reaction: When an alkali base is involved, the Wohl-Aue reaction causes an aniline and an aromatic nitro molecule to react, producing phenazine. An illustration is the reaction of nitrobenzene with aniline.

Diazotization: When aniline and its ring-substituted derivatives react with nitrous acid, diazonium salts are produced. These intermediates can be used in Sandmeyer reactions to change the amine group into -OH, -CN, or a halide. This diazonium salt can be paired with phenol, NaNO₂, and benzene to produce the color benzene azo phenol.

Informative Details Certain foods, including corn, wheat, apples, rhubarb, beans, and rapeseed cake, may contain small quantities of aniline (animal feed). Black tea has been found to contain aniline, a volatile substance. Both surface water and drinking water have been found to include aniline.

Aniline Structure

Aniline, also termed phenylamine or aminobenzene, has 6 carbon (C) atoms, 7 hydrogens (H) atoms, and 1 nitrogen (N) atom, giving it a chemical formula of C₆H₇N or C₆H₅NH_2.

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Because aniline has an amino group, it can be classified as an aromatic amine because it is also an amine. The phenyl group (C₆H₅) can be related to the amino group (NH₂), as shown in the formula, giving C₆H₅NH₂.

It is a chemical substance that burns easily and smells bad. The chemical can dissolve in water. In terms of colour, it can vary from white to light brown.

Have You Heard? Short-term contact with aniline dyes can irritate the eyes and have severe blood-related consequences, including methemoglobinemia, which can harm the kidneys and produce cyanosis and other symptoms. For people, it might be fatal. Methemoglobinemia results from prolonged or recurrent exposure that may affect the kidneys, liver, blood, and spleen (see short-term exposure). A probable carcinogen is an aniline (benzenamine).

Uses of Aniline

Aniline dyes are mostly utilized to create methylenedianiline and related chemicals by condensation with formaldehyde. The diamines are consolidated with phosgene to create methylene diphenyl disocyanate, a predecessor to urethane polymers. Further uses of aniline dyes include the production of herbicides (2%), colour dyes and pigments (2%), and compounds for rubber manufacturing. Aniline derivatives, such as phenylenediamines and diphenylamine, are antioxidants used as rubber additives. Paracetamol is an example of a drug made from aniline (acetaminophen, Tylenol). Aniline is primarily used as a preliminary to indigo, the colour of blue denim, in the dye business.

Thus, anilines are used in many practical and scientific applications. 

• In the rubber industry, anilines are used to create rubber chemicals and products such as gloves, balloons, and car tyres.
• Making clothes like jeans and other comparable products serves as a colouring agent.
• It is used to manufacture drugs, including paracetamol, acetaminophen, and Tylenol.
• It is used as a fungicide and insecticide in the agriculture sector.
• It is employed in synthesizing polyurethane, which is subsequently employed in manufacturing plastics.

Informative Details Aniline can be produced from the breakdown of specific contaminants found in ambient air, polymers, or tobacco burning.

What is Aniline Leather?

Aniline leather, also called pure, or full aniline leather, is the most natural leather. Aniline leather is dyed in vats using soluble dyes to ensure that the colour penetrates through the material and gives the leather its luscious and rich colour. No protective layer or surface colouring is used to preserve the natural texture and appearance of the material. The leathers also retain their original marks and texture, which adds to their authenticity. Lack of care, however, may make the leathers more prone to fading, staining, or peeling and cause colour changes on the material’s surface.

Advantages

• This premium aniline leather offers a lot of benefits. Due to its numerous wonderful characteristics, leather is one of the most sought-after materials. Full-grain leather was used to make it. 
• It is layered with the greatest density of fibers. It is as durable as leather can get. Aniline leather is highly durable due to the closely packed leather fibers. In addition, this kind of leather can withstand time to withstand wear and tear. 
• However, it is also soft and flexible in addition to being robust. Aniline is easier to work with than the majority of full-grain leather.
• Of course, one of its many benefits is also the way it looks. Due to its natural grain feature, it gives a pleasant appearance. With time it forms a patina as the leather absorbs body oils. It is something that typically exudes a retro vibe, drawing people towards leather.

Disadvantages

Even aniline leather has problems. Even with all of its advantages, this leather has certain drawbacks. The cost of aniline leather is one of their main drawbacks. High-quality leather is expensive to produce and purchase raw materials. Only the finest raw materials are suitable for aniline leather. Numerous of these elements contribute to aniline leather’s huge costs. This kind of leather has drawbacks against the outdoors and its expense. Direct sunlight often causes the leather to degrade. It is also particularly prone to stains and marks. Therefore, experts advise not to use aniline leather in homes with small children and pets. Despite being a fantastic leather, it is not resistant to the weather and children.

Conclusion

Aniline dye compounds are classified as aromatic amines and are considered to be naturally toxic. Aniline dyes are recognized to have all the traits of an aromatic chemical and are employed in various industrial applications. The chemical formula of aniline compounds is C6H5NH2, where the amino group is thought to be connected to the phenyl group.

Frequently Asked Question’s on Aniline

1.Why is aniline poisonous?

Aniline irritates the skin, eyes, and respiratory system. Any exposure could have negative effects. Aniline produces methemoglobinemia, which can lower the oxygen supply to organs. Additionally, aniline can cause the breakdown of red blood cells, which might cause hemolytic anemia immediately or later.

2.How is aniline produced?

Commercially, aniline is produced through the catalytic hydrogenation of nitrobenzene or through the reaction of chlorobenzene with ammonia. Iron borings dissolved in aqueous acid can also be used for nitrobenzene reduction. Aniline is a basic aromatic amine that reacts with mineral acids to create salts.

3.What are the applications of aniline?

 Aniline is utilized in manufacturing herbicides, diphenylamine, phenolics, and fungicides and is employed as isocyanates for urethane foams, rubber accelerators, dyes, intermediates, photographic chemicals, and antioxidants.

4.What are aniline used for?

Aniline dyes are mostly utilized to create methylenedianiline and related chemicals by condensation with formaldehyde some example – In rubber industry to create products such as gloves, balloons, and car tyres. 

5.What is diphenylamine used for?

Diphenylamine is frequently used in industry as an antioxidant, dye mordant, reagent, and fungicide as well as an antihelmintic and a fungicide in agriculture. 

6.Is aniline an acid or base?

Aniline is a weak base. 

7.Is aniline and benzenamine the same?

Aniline (benzenamine) is a probable carcinogen. It does not remain in the body due to its breakdown and removal.