NEET Study Notes for Organic Compounds Containing Nitrogen: Compounds that primarily consist of carbon atoms that bond covalently with either carbon, hydrogen atoms, or nitrogen and oxygen atoms. These are formed by natural processes of living beings that are called organic compounds. Examples of Organic compounds are protein and hydrocarbons. These produce long chains and complex structures.

• The chemical reactions in plant and animals cells are also due to certain organic compounds. These organic compounds can be mainly classified into Functional groups of homologous series.
• In NEET Chemistry Syllabus, Organic Chemistry consists of a weightage of around 34%. With NEET Study Notes for Organic Compounds Containing Nitrogen, candidates will be able to prepare well for NEET 2022.

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Important Topics for Organic Compounds Containing Nitrogen

Amines

The derivatives of ammonia in which alkyl groups replace one or more hydrogen atoms are called Amines. These can be found in vitamins, hormones, proteins, etc. Amines can be used for drug and detergent manufacturing.

Classification of Amines

Amines can be classified based on the number of hydrogen atoms are replaced by alkyl or aryl groups of ammonia into primary, secondary, and tertiary. On replacement of one hydrogen atom, primary amines 1 is formed, On replacement of two hydrogen atoms, secondary amines are obtained, on replacement of three hydrogen atoms, tertiary amines are obtained.

Nomenclature of Amines

To name amines, one method is to add the prefix the name of the alkyl group to the amines. The the nomenclature is alkamines. In the presence of two or three identical groups, di, and tri are added before the alkyl group name.

In the presence of more than one amine group, its position can be determined by numbering the carbon atoms present in the parent chain.

Some of the nomenclatures of Amines are

Structure of Amines

The nitrogen atom present in amines is sp3 hybridized The number of valence electrons in nitrogen is 5. The presence of a lone pair in and the three hybrid atomic particles that form a bond. One hybrid atomic orbital consists of an unshared pair of electrons.

This gives amines a pyramidal structure. Based on the electronic configuration of amines, orbitals of hydrogen or carbon overlap with an orbital of nitrogen that is sp3 hybridized. The bond angels of C-N-H is tetrahedral with the angle of amines around 107 degrees.

Physical Properties of Amines

• Amines that are lower aliphatic are in a state of the gas. At room temperature, Primary Amines are in a liquid state with three to four carbons atoms. If the carbon atoms are more, Amines will be in solid-state.
• Aniline and Arylamines are colorless, but if they are kept in open, they will be colored due to the oxidation in the atmosphere.
• Lower aliphatic amines are soluble in water as hydrogen bonds with water molecules are formed. With an increase in the size of the hydrophobic alkyl part, the molar mass of amine also increases which leads to less solubility in water. Higher aliphatic amines are insoluble in water.
• Amines readily dissolve in organic solvents like alcohol, benzene, and ether. In comparison to Amines, higher polarity is witnessed in Alcohol. Thus there is the formation of strong hydrogen intermolecular bonds.
• Due to the bonding between nitrogen and hydrogen molecules, ( hydrogen bonding) primary as well as secondary amines undergo intermolecular association.
• The presence of two hydrogen atoms makes the intermolecular association between primary amines more evident than secondary amines.
• Free Hydrogen atom for bonding is not present in tertiary amines, thus there is no intermolecular association between them.

Also, Read

• NEET Study Notes on Solid State
• NEET Study Notes for Aldehydes, Ketones and Carboxylic Acid

Chemical Properties of Amines

Amine is reactive due to the electronegativity difference in hydrogen and nitrogen atoms. A lone pair of electrons is also present in the nitrogen atom. The main difference between different reactions in primary, secondary, and tertiary amines is due to the number of hydrogen atoms attached to the nitrogen. The unshared electrons in amines, make them act like nucleophiles.

• Basicity- Amines form salts reacting with acids, due to their basic nature. These salts react with bases like NaOH to form the parent amine. Amine salts dissolve in water but not in organic solvents like alcohol and ether. Amines can be separated from non-basic organic compounds by undergoing this reaction.

Basicity of Amines is affected by the presence of an electron-donating group which leads to an increase in Basicity of Amines. However, due to the electron-withdrawing group, the basicity of amines is decreased.

The basic nature of amines is witnessed by the reaction of amines and mineral acids which form ammonium salts.

• Acylation- Acylation is the process of reaction of Aliphatic, Aromatic, Primary, Secondary amines through the process of nucleophilic substitution reaction with anhydrides, esters, and acid chlorides. The reactions undergo when a strong base is present. The end products of alkylation are acid chlorides, anhydrides, and esters.

Classification of Amines

The number of hydrogen atoms that are replaced by ammonia molecule, amines can be classified into

• Primary Amines- In primary amines, one hydrogen atom is replaced by alkyl or aryl group. Examples of Primary Amines are Aniline, Methylamine, etc.
• Secondary Amines- In secondary amines, two hydrogen atoms are replaced by organic substituents. Examples- Diphenylamine, Dimethylamine, etc.
• Tertiary Amines- In tertiary amines, three hydrogen atoms are replaced by aryl or aromatic groups. Example- EDTA, Trimethylymine

Also Read

• NEET Study Notes for p block elements
• NEET Study Notes for Polymers

Preparation of Amines

The methods for the preparation of Amines are:

• Reduction of Nitriles- On reduction of nitriles with lithium aluminum, primary amines are formed. Animes that consist of more than one carbon atom are prepared by this method
• Gabriel Pthalmide Synthesis - Potassium salts of Pthalmide are formed when phthalimide is treated with ethanolic Potassium Hydroxide. Prime amine is obtained on further heating Potassium salt of Pthalmide with an alkyl halide, following the process of alkaline hydrolysis. Aromatic Primary Amines cannot be formed by this process as nucleophilic substitution does not occur in aryl halides. \
• Hoffman Bromide degradation reaction- In this method, amides are treated with bromine in NaOH aqueous or ethanolic solution. In this degradation reaction, the alkyl or aryl group shifts from the carbon atom of the amide group to the nitrogen atom. A primary amine is formed through this method. However, this amine has one less carbon atom than the original amide.
• Ammonolysis of Alkyl Halides- On reacting with ethanolic solution, alkyl benzyl halide, undergoes a nucleophilic substitution reaction. Here the amino group replaces the halogen atom. This process of splitting the C-X bond by ammonia molecule is called ammonolysis.
• Reduction of Nitro Compounds- Nitro compounds can be reduced to amines with the help of metals in an acidic medium or with the help of hydrogen gas in the presence of nickel, palladium, or platinum in fine form.

Uses of Amines

• Amines can be used for purifying water, manufacturing medicines, and making insecticides and pesticides.
• Amino Acids and several vitamins are also produced by amines.
• Analgesics like morphine and Demerol are produced from amines. Seratonin

Cyanides

Cyanide consists of one nitrogen and carbon atom that connects with each other by a triple bond. These are chemical compounds that act like poisons. Cyanide is formed by bacteria, algae, and fungi. Hydrogen Cyanide is colorless or pale blue liquid at room temperature.

Certain cyanides are in a white powder-like state. Example- potassium cyanide, sodium cyanide.

Cyanide can be used for mining gold silver, stabilization of electron ions, making jewelry, Cyanide can also be used as a food additive.

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Diazonium Salts

The group of organic compounds shares one common functional group where X is an organic or inorganic anion. R is an alkyl or aryl group. Examples- Halogen, Chlorine, Bromine, etc. On heating Diazoynm salts or diazonium compounds, in water, phenols is formed.

Properties of Diazonium Salt

• They are ionic in nature.
• They are soluble in water.
• Colorless crystalline solids include aryl diazonium salts.
• Benezenediazonium chloride is water-soluble whereas Benzenediazonium fluoroborate is not.

Preparation of Diazonium Salts

• Diazotization is the process of conversion of primary aromatic amines into diazonium salts. Generally, the organic compounds are converted.
• Diazonium salt should be used generally soon after its formation because it is highly stable and cannot be stored.
• On the reaction of aromatic amine and nitrous acid, diazonium salt like benzene diazonium chloride is formed.

NEET Sample MCQs on Organic Compounds containing Nitrogen

Question: Name the functional group of Nitrogen

1. Barium
2. Helium
3. Oxygen
4. Nitrogen

Answer: Nitrogen

Question: On treating ethylamine with methyl magnesium bromide, what is obtained?

1. Ethanol
2. Ethane
3. Methanol
4. Methane

Answer: Methane

Question: What is formed on treating primary amines with acid chlorides?

1. Tertiary Amine
2. Isocyanides
3. Acetaldehyde
4. Amides

Answer: Amides

Question: Which process helps in the preparation of lower amines/

1. Hoffman bromamide reaction
2. Schmidt reaction
3. Wurtz reaction
4. Mannich reaction

Answer: Hoffman bromamide reaction

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