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Last updated date: 18th Apr 2024
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An Introduction

Organic chemistry is a beautiful and magical subject if you happen to understand the core of the subject. Aniline is one such interesting organic compound with versatile materials and diverse industrial applications. 

This article is complied to discuss in detail the concept of Anilines. The sole aim is to make the students fall in love with the subject to an extent that scoring high marks will no longer be an unachievable task. 

In this article, we shall be discussing - 

  • Aniline - an introduction

  • What is Aniline?

  • Anilines Structure

  • Anilines Physical Properties

  • Anilines Reactions

  • Anilines applications

  • Frequently asked questions


What is Anilines?

Aniline is a type of organic base which is used in the making of several dyes, explosives, plastics, drugs, and rubber, and photographic chemicals. Anilines are the organic compounds that lie in the class of groups coming in the organic chemistry that is referred to as aminobenzene or phenylamine. These compounds are known to be toxic and to be one of the classes of the aromatic amines. They are used in a variety of industrial applications and possess all the characteristics of that of an aromatic compound. The aniline compounds are known to have the formula C6H5NH2 in which the amino group is attached to the phenyl group.


Aniline occurs in the form of a yellowish and slightly brownish oily liquid which has a fishy and a musty odour. It smells like a rotten fish. It is a chemical substance that is a flammable liquid and has a very unpleasant odour. The compound of aniline is soluble in water which is colourless to light brown. Its chemical formula is C6H5NH2 or C6H7N. Since it consists of 6 carbon atoms, 7 hydrogen atoms, and 1 nitrogen atom in its chemical formula, it is an organic compound. Today, we will learn about what is anilines, the phenylamine structure, its physical properties and uses.


Anilines Structure C6H5NH2 Structure

Given below is the aminobenzene structure.


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The structure of benzenamine has a pyramidal shaped molecule and has a nitrogen hybridization which lies in between sp3 and sp2. Due to this, the nitrogen lone pair lies in an spx hybrid orbital and has a high p character. The amino group in aniline is much flatter than that in an aliphatic amine, which is because of the conjugation of the lone pair of electrons along with the aryl substituent.


Anilines Physical Properties

Let us discuss the physical properties of anilines which are given below.

  1. The boiling of aniline is 184.13 °C and its melting point is −6.3 °C.

  2. The compound of aniline is slightly soluble in water and many times freely soluble in the chemicals like alcohol and ether.

  3. This organic compound turns darker when it is exposed to light and air.

  4. It is known to be a weak base and when it reacts with strong acids, it tends to form an anilinium ion C6H5N3+.

  5. It is said to be toxic when it is inhaled via the air or tends to get absorbed into the skin since it produces nitrogen oxides that are harmful to the human body as well as the environment.


Anilines Reactions

Let us now take a look at some of the reactions of anilines and the aniline compounds.

  1. Oxidation Reaction: Oxidation reactions of the anilines compounds tend to lead to the formation of the carbon-nitrogen bonds.

  2. Basicity: Anilines are weaker bases and on reacting with stronger acids, the compounds form anilinium ions.

  3. Acylation: In the acylation reaction, anilines tend to react readily with the carboxylic acids and form amides.

  4. The other reactions of anilines consist of alkylation reaction, hydrogenation, Diazotization, Wohl-Aue reaction, etc.


Anilines Uses

Anilines are used in various fields of science and everyday life. Some of the uses of anilines are given below.

  1. Anilines have their uses in the rubber industry to process the rubber chemicals and products like car tyres, gloves, balloons, etc.

  2. It is also used as a dyeing agent for the manufacturing of clothes like jeans, etc.

  3. It is used for the production of drugs, for example, paracetamol, acetaminophen, and Tylenol.

  4. It is also used in the form of pesticides and fungicides when it comes to the agricultural industry.

  5. It is also used for the manufacturing of polyurethane which is then used for making plastics.

FAQs on Anilines

1. Is aniline toxic for human health?

An aniline has wide industrial usage, and the most closer exposure humans can have to aniline is through its use in the agriculture sector in the form of insecticides and pesticides. So, according to the research of various organizations, it has been found that aniline has certain carcinogenic elements which enter the human body either through direct exposure or indirect consumption. Direct exposure is when farmers inhale the compound while spraying it on the plants and indirectly through consuming those plants which have made the use of aniline. Thus, various industries are deciding on a limit beyond which aniline cannot be used. 

2. What is the difference between Ethyle amine and aniline?

The difference between Ethyle amine and aniline are as - 

  • Ethylamine has the chemical composition as C2H5NH2, while aniline has a composition as C6H5NH2. There is a difference between the 3 atoms of carbon. 

  • Ethylamine is soluble in water while aniline is insoluble in water

  • The odor of Ethylamine is similar to ammonia while it is not the case in aniline

  • When NaNO2 + HCL is combined with Ethylamine, it forms ethyl alcohol. Whereas, when it is combined with aniline it forms Benzene diazonium chloride which when heated gives phenol. 

  • Ethylamine turns red litmus to blue while aniline performs no action. 

3. What is the process of conversion from Benzene to aniline?

The process is very simple, please follow:

  • Take Benzene which is C6H6 

  • We add HNO3 (Nitric Acid) and H2SO4 (Sulphuric Acid) through Nitration in benzene

  • NO2 will bond with the benzene to form Nitrobenzene, to which hydrogen (6(H)) will be further added

  • Hydrogen will be added in the presence of Tin (Sn) and hydrochloric acid (HCl) 

  • Oxygen from the NO2 will be replaced and two atoms of hydrogen will form a bond with nitrogen to give NH2

  • Finally to give us aniline from benzene. 

4. What is diazotization?

In simple words, the preparation of diazonium salt is called diazotization. Here diazonium can be understood as ‘Diaz’ which means 2N(two nitrogen) and ‘ium’ means a positive charge of the atom. So diazonium salt is R−N2⁺ .Here R can be any organic group, like an alkyl or an aryl. In the diazotization process, we need 1-degree amine as it is not possible in 2 degrees or 3-degree amine. 

5. Do we need to remember all the chemical formulas for aniline and related topic?

In chemistry, it is very essential for the students to know the chemical formulas. Only when you know how to identify any compound with its chemical representation, you will be able to solve questions in exams or write answers in the paper. However, you don't need to mug any of these chemical formulas or equations, rather try to understand them conceptually and keep revising these concepts. The faculties at Vedantu aims to simplify the learning process for you. Watch the video lectures on various topics made available to enhance your preparation. 

6. Why is Aniline a Weaker Base?

Aniline is a weaker base since the lone pair over the nitrogen atom in the NH2 group is in conjugation with the π-electrons that are present in the benzene ring. Due to this, it is not readily available for the donation. A weaker base is the one that tends to donate its lone electron pair. Since the pi-electrons are not readily available for donation from the benzene ring, it makes for a weaker base.

Also, the weaker basicity of anilines is due to the inductive effect from the electronegative sp2 carbon atom and the resonance effects, as the electron lone pair of nitrogen is delocalized partially into the pi system of a benzene ring.

7. What is the IUPAC Name of Aniline?

The IUPAC name of aniline is Benzenamine. However, it is also called benzamine or phenylamine.Chemically, aniline is known to be an electron-rich derivative of benzene, and as a consequence, it tends to react rapidly in the electrophilic aromatic substitution reactions. Similarly, it is also prone to oxidation reactions. Aniline can also be diazotized for giving a diazonium salt, which then tends to undergo many nucleophilic substitution reactions.