Grade 12
  1. Solid state  1.1. Classification of solids  1.2. Crystal Lattice and Unit Cell  1.3. Packing Efficiency  1.4. Density of unit cell  1.5. Imperfections in solids (point and line defects)  1.6. Electrical Properties of Solids (Conductors, Insulators and Semiconductors)  1.7. Magnetic Properties of Solids (Diamagnetic, Paramagnetic and Ferromagnetic Materials)
  2. Solution  2.1. Types of Solutions (Homogeneous and Heterogeneous)  2.2. Expressing concentration of solutions (mass %, volume %, molarity, molality, normality, mole fraction)  2.3. Solubility of solids and gases in liquids (Henry's law)  2.4. Raoult's Law and Ideal and Non-Ideal Solutions  2.5. Syndrome properties  2.6. Abnormal molar mass and Van't Hoff factor
  3. Electrochemistry  3.1. Electrochemical cells (galvanic and electrolytic cells)  3.2. Galvanic cell and EMF of the cell  3.3. Standard electrode potential and electrochemical series  3.4. Nernst equation and its applications  3.5. Conductivity and electrolytic cells (specific, molar and equivalent conductivity)  3.6. Kohlrausch's law and its applications  3.7. Batteries (primary and secondary cells)  3.8. Corrosion and its prevention
  4. Chemical kinetics  4.1. Rate of chemical reaction  4.2. Factors affecting the reaction rate (concentration, temperature, catalyst, surface area)  4.3. Order and molecularity of the reaction  4.4. Integrated Rate Equations (Zero, First and Second Order)  4.5. Half-life of a reaction  4.6. Collision theory and activation energy  4.7. Arrhenius equation and its applications
  5. Surface chemistry  5.1. Adsorption and its types (Physicosorption and Chemisorption)  5.2. Catalysis and its types (homogeneous and heterogeneous)  5.3. Colloids and their properties (Tyndall effect, Brownian motion, coagulation)  5.4. Emulsions and gels  5.5. Applications of Colloids
  6. General principles and processes of separation of elements  6.1. Presence of metals and minerals  6.2. Concentration of ores (gravity separation, froth flotation, magnetic separation)  6.3. Extraction of raw metals (roasting, calcination, reduction)  6.4. Thermodynamic and electrochemical principles of metallurgy  6.5. Refining of metals
  7. P-block elements  7.1. Group 15 elements (nitrogen and phosphorus)  7.2. Group 16 Elements (Oxygen, Sulphur and their Compounds)  7.3. Group 17 Elements (Halogens and their Compounds)  7.4. Group 18 Elements  7.5. Properties and Trends in p-Block Elements  7.6. Important compounds of p-block elements (ammonia, phosphine, sulphuric acid, hydrochloric acid)  7.7. Interhalogen compounds and their applications
  8. d-block and f-block elements  8.1. General Properties of Transition Metals  8.2. Properties of Inner Transition Metals (Lanthanoids and Actinoids)  8.3. Lanthanoid and actinoid contractions  8.4. Coordination Chemistry of d-Block Elements
  9. Coordination compounds  9.1. Werner's theory and modern concepts  9.2. Coordination number and type of ligand  9.3. Nomenclature of Coordination Compounds  9.4. Isomerism (geometrical and optical) in coordination compounds  9.5. Bonding in Coordination Compounds (Valence Bond Theory and Crystal Field Theory)  9.6. Stability and applications of coordination compounds in medicine and industry
  10. Haloalkanes and haloarenes  10.1. Classification and nomenclature of haloalkanes and haloarenes  10.2. Physical and Chemical Properties of Haloalkanes and Haloarenes  10.3. Mechanism of Nucleophilic Substitution Reactions (SN1 and SN2)  10.4. Uses and environmental effects (ozone depletion, CFCs)
  11. Alcohol, phenol and ether  11.1. Structure and classification of alcohols, phenols and ethers  11.2. Preparation and properties of alcohols  11.3. Preparation and properties of phenol  11.4. Preparation and properties of ethers  11.5. Chemical Reactions and Uses
  12. Aldehydes, ketones and carboxylic acids  12.1. Structure and nomenclature in aldehydes, ketones and carboxylic acids  12.2. Preparation and properties of aldehydes and ketones  12.3. Chemical reactions in aldehydes, ketones and carboxylic acids (nucleophilic addition, oxidation and reduction)  12.4. Preparation and Properties of Carboxylic Acids  12.5. Chemical Reactions and Uses of Carboxylic Acids
  13. Nitrogen-containing organic compounds  13.1. Amines (classification, structure, basicity)  13.2. Preparation and properties of amines  13.3. Reactions of Amines (Diazotization, Carbylamine Reaction)  13.4. Diazonium salts and their applications in paint industry
  14.1. Carbohydrates (classification and properties)  14.2. Proteins (Structure and Function)  14.3. Enzymes (Mechanism and Function)  14.4. Nucleic acids (DNA and RNA)  14.5. Vitamins and hormones
  15. Polymer  15.1. Classification of Polymers (Addition, Condensation, Copolymers)  15.2. Types of polymerization (free radical, ionic, condensation)  15.3. Important Polymers and Their Uses  15.4. Biodegradable and non-biodegradable polymers
  16. Chemistry in Everyday Life  16.1. Drugs and their classification (analgesics, antipyretics, antibiotics, antacids)  16.2. Chemicals in food and cosmetics (preservatives, artificial sweeteners, antioxidants)  16.3. Cleaning agents and detergents (soaps, synthetic detergents, surfactants)  16.4. Environmental Chemistry (Pollution, Green Chemistry, Sustainable Chemistry)

Grade 12 → Nitrogen-containing organic compounds ↓


Preparation and properties of amines


Introduction

Amines are important organic compounds that contain nitrogen. They are derived from ammonia (NH 3) and are characterized by the presence of a nitrogen atom bonded to one or more alkyl or aryl groups. Amines play important roles in both organic and biological chemistry and are found in many biological molecules such as amino acids, proteins, hormones, and vitamins.

Structure of amines

Amines can be classified based on the number of carbon-containing groups attached to the nitrogen atom:

  • Primary amine: One carbon group attached to nitrogen. Example: methylamine (CH 3 NH 2).
  • Secondary amines: Two carbon groups attached to a nitrogen. Example: dimethylamine ((CH 3) 2 NH).
  • Tertiary amine: Three carbon groups attached to a nitrogen. Example: trimethylamine ((CH 3) 3 N).

Preparation of amines

1. Reduction of nitro compounds

A common method for preparing amines is the reduction of nitro compounds. Nitro compounds, which contain -NO 2 group, are reduced to amines using various reducing agents:

R-NO 2 + 6[H] → R-NH 2 + 2H 2 O

Common reducing agents include:

  • Hydrogen gas (H 2) with a metal catalyst such as palladium, platinum or nickel.
  • Iron powder and hydrochloric acid.
  • Tin and hydrochloric acid.

2. Reduction of amides

Amides can be reduced to amines using a strong reducing agent such as lithium aluminium hydride (LiAlH 4).

RCONH2 + 4[H] → R- CH2NH2 + H2O

3. Gabriel phthalimide synthesis

The Gabriel phthalimide synthesis is used to prepare primary amines. In this method, potassium phthalimide is reacted with an alkyl halide to form an N-alkyl phthalimide. Hydrolysis of the alkylated intermediate yields the primary amine.

O=C , C 8 H 4 O 3 N - K + + RX → C 8 H 4 O 2 NR → RNH 2

4. From alkyl halides

Amines can also be prepared by reacting an alkyl halide with ammonia, undergoing a nucleophilic substitution reaction.

RX + NH3 → R- NH2 + HX

Properties of amines

Physical properties

Boiling point: Amines generally have higher boiling points than hydrocarbons because they have less hydrogen bonding, but lower than alcohols because they have less hydrogen bonding. For example, ethylamine has a higher boiling point than ethane but lower than ethanol.

Solubility: Lower aliphatic amines are soluble in water due to their ability to form hydrogen bonds. However, solubility decreases with increase in molecular size due to the hydrophobic nature of the alkyl group.

Chemical properties

Amines have a diverse chemical behaviour and participate in many reactions, which are described below.

1. Originality

Amines are basic due to the presence of a lone pair of electrons on the nitrogen atom, which can accept a proton. This characteristic leads them to act as Lewis bases. An example of this is reacting with acids to form ammonium salts.

RNH 2 + HCl → RNH 3 Cl

2. Alkylation

Amines react with alkyl halides in a series of nucleophilic substitution reactions, resulting in the formation of secondary and tertiary amines and quaternary ammonium salts.

RNH2 + R'X → RR'NH + HX

3. Acylation

Amines undergo acylation reactions with acyl chlorides or anhydrides to form amides. This is a nucleophilic acyl substitution reaction.

RNH2 + R'COCl → RNHCO-R' + HCl

4. Reaction with nitrous acid

Primary aliphatic amines react with nitrous acid to form alcohols and evolve nitrogen gas.

RNH2 + HONO → ROH + N2 + H2O

Aromatic amines such as aniline react with nitrous acid to form diazonium salts.

C 6 H 5 NH 2 + HONO + HCl → C 6 H 5 N 2 Cl + 2H 2 O

5. Formation of Schiff base

Amines react with aldehydes or ketones to form imines, also known as Schiff bases. This condensation reaction occurs mainly with primary amines.

RNH2 + R'CHO → RN=CHR' + H2O

Visual representation of amines

Primary amine R- NH2 Secondary amine (R) 2 -NH

Applications of amines

Amines are used in the synthesis of many pharmaceuticals and dyes. Additionally, they are used in the manufacture of polymers and as intermediates in the production of agricultural chemicals and surfactants.

Conclusion

Understanding the preparation and properties of amines is important because they have wide applications in various fields including pharmaceuticals and chemical synthesis. The structural features and chemical reactivity of amines continue to fascinate chemists, enabling the synthesis of new compounds to meet industrial demands.


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Amines (classification, structure, basicity)
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Reactions of Amines (Diazotization, Carbylamine Reaction)

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Preparation and properties of amines

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