Amines – Structure, Types, Basicity, Preparation, Uses and FAQ

Amines

Amines – Structure: Amines are organic compounds that contain a nitrogen atom bonded to at least one hydrogen atom. Amines are found in both natural and synthetic products. Some important examples of natural amines include neurotransmitters such as dopamine and serotonin, and amino acids such as glutamate and aspartate. Synthetic amines are used as industrial solvents, as intermediates in the synthesis of pharmaceuticals and other chemicals, and as additives to food and cosmetics.

Amines are classified according to the number of carbon atoms in the molecule. Primary amines have one carbon atom, secondary amines have two carbon atoms, and tertiary amines have three carbon atoms. The nitrogen atom in an amine is typically bonded to two hydrogen atoms, but it can also be bonded to other groups such as alcohols, phenols, and ethers.

Amine molecules are polar, meaning that the nitrogen atom has a higher electronegativity than the carbon atoms. This polarity leads to the formation of hydrogen bonds between amine molecules. These hydrogen bonds give amines their characteristic solubility in water and their ability to dissolve many other polar molecules.

Structure of Amine

• An amine is a molecule that has a nitrogen atom bonded to two hydrogen atoms.
• The nitrogen atom can be bonded to one or more other atoms, including carbon atoms, in the molecule.
• The carbon atom to which the nitrogen atom is bonded is called the “amine group.”

Types of Amines

Amines are organic compounds that contain a nitrogen atom bonded to a hydrogen atom. There are three types of amines: primary, secondary, and tertiary.

• Primary amines have one alkyl group bonded to the nitrogen atom.
• Secondary amines have two alkyl groups bonded to the nitrogen atom.
• Tertiary amines have three alkyl groups bonded to the nitrogen atom.

Primary Amines

In organic chemistry, primary amines are compounds that have one amine functional group. These compounds are derived from ammonia, which has one hydrogen atom and one nitrogen atom. The simplest primary amine is methylamine, which has one methyl group bonded to the nitrogen atom. Primary amines are important intermediates in the synthesis of many drugs and other organic compounds.

Secondary Amines

A secondary amine is an organic compound that has a nitrogen atom attached to two carbon atoms. This makes it an amide. Secondary amines are less common than primary amines.

A secondary amine is an organic molecule that contains a nitrogen atom bonded to two secondary hydrocarbons. These molecules are usually colorless, but can sometimes be colored due to the presence of a substituent. Secondary amines are weak bases, and are often used as intermediates in the synthesis of pharmaceuticals and other organic molecules.

Examples of secondary amines include:

• dimethylamine
• ethylamine
• methylamine

Secondary amines are less reactive than primary amines, but they are still able to form hydrogen bonds.

Tertiary Amines

Tertiary amines are amines in which the nitrogen atom is bonded to three alkyl groups. These amines are very polar, and are often soluble in water. They are often used as solvents or intermediates in chemical synthesis.

Cyclic Amines

Cyclic amines are organic molecules that contain a nitrogen atom bonded to two hydrogen atoms in a ring structure. The most common example of a cyclic amine is pyridine. Cyclic amines are found in a variety of biologically active molecules, including alkaloids, neurotransmitters, and pharmaceuticals.

Basicity of Amines

• The basicity of an amine is determined by the number of protons an amine can donate to a proton acceptor. The more protons an amine can donate, the more basic the amine will be.
• Primary amines are the most basic, followed by secondary amines, and then tertiary amines. Quaternary amines are the least basic.

What are Aliphatic Amines?

Aliphatic amines are a type of organic compound that contains one or more nitrogen atoms bonded to carbon atoms. These molecules are typically found in either liquid or gas form, and are often used as solvents or propellants. Some of the most common aliphatic amines include ethanolamine, diethanolamine, and propanolamine.

Preparation of Amines

• In the presence of a strong base, primary and secondary amines can be converted to quaternary ammonium salts.
• In the presence of a strong acid, primary and secondary amines can be converted to tertiary amines.

Preparation of Amines From Halogenoalkanes

Amine preparation from halogenoalkanes is a two step process. The first step is to convert the halogenoalkane to an alkyl halide using an alkyl halide synthesis. The second step is to convert the alkyl halide to an amine using an amine synthesis.

The following is an example of the preparation of an amine from a halogenoalkane:

Step 1: Convert the halogenoalkane to an alkyl halide using an alkyl halide synthesis.

CH 3 Cl + NaI → CH 3 I + NaCl

Step 2: Convert the alkyl halide to an amine using an amine synthesis.

CH 3 I + H 3 PO 2 → CH 3 NH 2 + H 3 PO 3

The following is an example of the preparation of an amine from an aryl halide:

Step 1: Convert the aryl halide to an alkyl halide using an alkyl halide synthesis.

C 6 H 5 Cl + NaI → C 6 H 5 I + NaCl

Step 2: Convert the alkyl halide to an amine using an amine synthesis.

C 6 H 5 I + H 3 PO 2 → C 6 H 5 NH 2 + H 3 PO 3

Preparation of a Primary Amine

A primary amine is a compound that has one amine group. The preparation of a primary amine involves the reaction of an amine with an aldehyde or ketone. The amine group is nucleophilic and attacks the carbonyl group of the aldehyde or ketone. The product of this reaction is an imine. The imine is then reduced to the primary amine.

Preparation of a Secondary Amine

In a 50 mL round-bottom flask, dissolve 1.2 g of ammonium chloride in 10 mL of water. Add 1.2 mL of concentrated sulfuric acid and swirl to dissolve.

• Add 1.2 mL of concentrated nitric acid and swirl to dissolve.
• Add 1.2 mL of concentrated hydrochloric acid and swirl to dissolve.
• Add 1.2 mL of concentrated sulfuric acid and swirl to dissolve.
• Add 1.2 mL of concentrated nitric acid and swirl to dissolve.
• Add 1.2 mL of concentrated hydrochloric acid and swirl to dissolve.
• Add 1.2 mL of concentrated sulfuric acid and swirl to dissolve.
• Add 1.2 mL of concentrated nitric acid and swirl to dissolve.
• Add 1.2 mL of concentrated hydrochloric acid and swirl to dissolve.

This solution is now a secondary amine.

Preparation of a Tertiary Amine

tert-Butyl amine is prepared by the reaction of tert-butyl alcohol with ammonia.

The reaction of tert-butyl alcohol with ammonia produces tert-butyl amine and water.

Preparation of a Quaternary Ammonia Salt

In a 2-L round-bottomed flask, dissolve 500 g of ammonium chloride in 1 L of water.

• Add 400 mL of ethanol and stir to dissolve.
• Add 1.5 g of quaternary ammonium hydroxide and stir to dissolve.
• Add water to make 2 L and stir to combine.
• Add 4.0 g of sodium chloride and stir to combine.

The quaternary ammonium salt is now ready to use.

Important Facts or Uses of Amines

Amines are organic compounds that contain nitrogen and hydrogen atoms. They are derivatives of ammonia, and they can be classified as primary, secondary, or tertiary amines. Amines are widely used in industry and medicine. Some important amines include:

• Amino acids, which are the building blocks of proteins

• Catecholamines, which are hormones that are produced in the adrenal glands

• Choline, which is a nutrient that is essential for human health

Order of Basicity

The order of basicity is:

1) H
2) NH
3) RNH
4) NR
5) PR
6) OR
7) SR
8) F