Undergraduate
  1. General chemistry  1.1. Introduction to Chemistry  1.2. Atomic Structure  1.2.1. Subatomic particles  1.2.2. Atomic Model  1.2.3. Quantum numbers  1.2.4. Electron Configuration  1.2.5. Periodic trends  1.2.6. Isotopes and their applications  1.3. Chemical bond  1.3.1. Ionic bond  1.3.2. Covalent bonds  1.3.3. Metal Bond  1.3.4. Hybridization  1.3.5. Molecular geometry and VSEPR theory  1.3.6. Bond polarity and dipole moment  1.4. Stoichiometry  1.4.1. Mole concept  1.4.2. Empirical and molecular formula  1.4.3. Limiting reactant and excess reactant  1.4.4. Percent Yield and Purity  1.4.5. Dilution calculation  1.5. States of matter  1.5.1. Gas Laws  1.5.2. Matter and Intermolecular Forces  1.5.3. Solid and Crystal Structures  1.5.4. Phase diagram  1.5.5. Plasma and supercritical fluid  1.6. Chemical reactions  1.6.1. Types of Chemical Reactions  1.6.2. Balancing Chemical Equations  1.6.3. Thermochemical reactions  1.6.4. Reaction energy profiles  1.7. Solutions and Mixtures  1.7.1. Concentration units  1.7.2. Syndrome properties  1.7.3. Solubility and Solubility Rules  1.7.4. Henry's Law and Raoult's Law  1.7.5. Partition coefficient  1.8. Chemical equilibrium  1.8.1. Law of mass action  1.8.2. Le Chatelier's principle  1.8.3. Reaction quotient  1.8.4. To use this online calculator for Equilibrium Constant, enter Equilibrium Constant (Eq.) and hit the calculate button. Here is how the Equilibrium Constant calculation can be explained with given input values -> 0.05 = 0.05/0.  1.8.5. Acid-base balance  1.9. Acids and bases  1.9.1. Arrhenius, Brønsted–Lowry, and Lewis definitions  1.9.2. pH and pOH  1.9.3. Acid-base titration  1.9.4. Buffer Solution  1.9.5. Acid-base indicator  1.9.6. Polyprotic Acids and Bases  1.10. Electrochemistry  1.10.1. redox reactions  1.10.2. Galvanic and Electrolytic Cells  1.10.3. Nernst equation  1.10.4. Electrolysis  1.10.5. Faraday's laws of electrolysis  1.11. Thermodynamics  1.11.1. Laws of Thermodynamics  1.11.2. Enthalpy, entropy and Gibbs free energy  1.11.3. Spontaneity of reactions  1.11.4. Thermodynamic cycles (Hess's law, Carnot cycle)  1.12. Kinetics  1.12.1. Rate law and reaction order  1.12.2. Activation Energy and Catalyst  1.12.3. Collision theory  1.12.4. Reaction mechanism  1.12.5. Transition state theory
  2. Organic chemistry  2.1. Structure and relationships  2.1.1. Hybridisation in Carbon Compounds  2.1.2. Resonance and aromatization  2.1.3. Molecular orbitals  2.1.4. Inductive and mesomeric effects  2.2. Hydrocarbons  2.2.1. Hydrocarbons  2.2.2. Alkene  2.2.3. Alkynes  2.2.4. Aromatic compounds  2.2.5. Cycloalkanes and Conformation  2.3. Functional Group  2.3.1. Alcohols and phenols  2.3.2. Ethers and epoxides  2.3.3. Aldehyde and ketone  2.3.4. Carboxylic acids and derivatives  2.3.5. Amin  2.3.6. Esters and amides  2.3.7. Thiols and sulfides  2.4. Stereoscopic  2.4.1. Isomerism in Stereochemistry  2.4.2. Chirality and optical activity  2.4.3. Structural analysis  2.4.4. Diastereomers and Enantiomers  2.5.1. Substitution reactions  2.5.2. Elimination reactions  2.5.3. Addition reactions  2.5.4. Radical reactions  2.5.5. Rearrangement reactions  2.5.6. Pericyclic Reactions  2.6. Spectroscopy and structural analysis  2.6.1. Infrared Spectroscopy  2.6.2. Nuclear magnetic resonance spectroscopy  2.6.3. Mass Spectrometry  2.6.4. UV-visible spectroscopy  2.6.5. X-ray crystallography  2.7. Polymer chemistry  2.7.1. Addition and Condensation Polymers  2.7.2. Polymerization mechanism  2.7.3. Biodegradable Polymer  2.7.4. Conducting and smart polymers
  3. Inorganic chemistry  3.1. Coordination chemistry  3.1.1. Ligands and coordination compounds  3.1.2. Crystal field theory  3.1.3. Molecular Orbital Theory in Coordination Compounds  3.1.4. Jahn–Taylor distortion  3.2. Main Group Chemistry  3.2.1. Alkali and alkaline earth metals  3.2.2. Halogens and Noble Gases  3.2.3. Transition metals and their complexes  3.2.4. Lanthanides and Actinides  3.3. Solid state chemistry  3.3.1. Crystal lattices and unit cells  3.3.2. Defects in solids  3.3.3. Electrical and magnetic properties  3.3.4. Superconductivity  3.4. Bio-inorganic chemistry  3.4.1. Metal ions in biology  3.4.2. Enzymatic reactions with metals  3.4.3. Metal poisoning and detoxification  3.4.4. Metalloproteins and Metalloenzymes
  4. Physical chemistry  4.1. Quantum Chemistry  4.1.1. Wave–particle duality  4.1.2. Schrödinger Equation  4.1.3. Quantum Numbers and Orbitals  4.1.4. Atomic and molecular spectroscopy  4.2. Statistical mechanics  4.2.1. Maxwell–Boltzmann distribution  4.2.2. Partitioning functions  4.2.3. Bose–Einstein and Fermi–Dirac statistics  4.3. Chemical thermodynamics  4.3.1. Gibbs Free Energy  4.3.2. Phase transition  4.3.3. Thermodynamic efficiency  4.4. Surface chemistry  4.4.1. Absorption and Catalysis  4.4.2. Colloids and Emulsions
  5. Analytical Chemistry  5.1. Classical methods  5.1.1. Gravimetric Analysis  5.1.2. titrimeter  5.2. Instrumental methods  5.2.1. Chromatography  5.2.2. Spectroscopy  5.2.3. Electroanalytical methods  5.2.4. X-ray diffraction
  6. Industrial Chemistry  6.1. Petrochemistry  6.2. Chemical engineering principles  6.3. Green Chemistry  6.4. Pharmaceuticals and Drug Synthesis
  7. Biochemistry  7.1. Carbohydrates  7.2. Proteins and enzymes  7.3. Lipids and membranes  7.4. Nucleic acids  7.5. Metabolism and Bioenergetics  7.6. Enzyme kinetics and mechanism

Undergraduate → Organic chemistry → Functional Group ↓


Amin


Introduction to amines

Amines are an important class of organic compounds that are derived from ammonia (NH3) by replacing one or more hydrogen atoms with alkyl or aryl groups. They play important roles in both industrial applications and biological systems. Amines can be classified as primary, secondary, or tertiary depending on the number of organic substituents attached to the nitrogen atom. Primary amines have one substituent, secondary amines have two, and tertiary amines have three substituents. The general formulas for these types of amines are:

Primary amine: RNH2
Secondary amine: R2NH
Tertiary amine: R3N

Structures and examples

Primary amine

In primary amines, an alkyl or aryl group is attached to the nitrogen atom. The simplest primary amine is methylamine. The structure of a primary amine is as follows:

        H
         |
    R - N
         |
        H

Examples of primary amines are:

  • CH3NH2 - methylamine
  • C2H5NH2 - ethylamine
  • C6H5NH2 - aniline

Secondary amine

In secondary amines, two alkyl or aryl groups are bonded to nitrogen. A simple example is dimethylamine:

        R
         |
    R - N
         |
        H

Examples of secondary amines include:

  • (CH3)2NH - dimethylamine
  • C2H5NHC2H5 - diethylamine
  • C6H5NHC2H5 - N-ethylaniline

Tertiary amine

Tertiary amines have three alkyl or aryl groups attached to the nitrogen atom. The simplest example is trimethylamine:

        R
         |
    R - N
         |
        R

Examples of tertiary amines include:

  • (CH3)3N - trimethylamine
  • C2H5N(C2H5)2 - triethylamine
  • C6H5N(CH3)2 - N,N-dimethylaniline

Physical properties of amines

Amines generally have a fishy odor, which is particularly strong in the case of lower aliphatic amines. They exhibit higher boiling points than alkanes of similar molecular weight, especially in primary and secondary amines, due to the presence of hydrogen bonding. However, compared to alcohols, amines have lower boiling points because nitrogen is less electronegative than oxygen, resulting in weaker hydrogen bonds.

Amines are also known for their solubility in water, which is mainly due to hydrogen bonding with water molecules. Primary and secondary amines are more soluble in water than tertiary amines due to stronger hydrogen bonding ability. Solubility decreases with the increase in the molecular weight of the amines.

Melting and boiling point

The boiling point of amines follows the following trend:

Primary > secondary > tertiary, for same molecular weight

This trend is attributed to the decreasing ability to form intermolecular hydrogen bonds.

Chemical properties of amines

Basicity

Amines are basic in nature due to the lone pair of electrons on the nitrogen atom, which allows them to accept protons. The basic strength of amines is affected by substituents, which can donate electron density to the nitrogen atom or withdraw electron density from it.

In the gaseous state the order of alkalinity is usually:

Primary > secondary > tertiary

However, in aqueous solution the order may change due to the dissolution of hydrogen bonds, often making tertiary amines less basic than secondary amines.

Jet

Nucleophilic substitution

Amines can participate in nucleophilic substitution reactions, where they react with alkyl halides to form substituted amines.

RNH2 + R'X → RR'NH + HX

Reaction with acids

Amines react with acids to form amine salts, which are usually crystalline solids at room temperature.

RNH2 + HCl → RNH3+ Cl-

Hoffman elimination

In the Hofmann elimination process, quaternary ammonium iodide is converted to an alkene and a tertiary amine:

[R4N]+ I- → Alkene + R3N + HI

Commercial importance and applications

Amines are used in the manufacture of dyes, drugs, and polymers. They serve as intermediates in the synthesis of pharmaceuticals and are often used as building blocks in organic synthesis. For example, Aniline is an important starting material in the production of polyurethane foam and other industrial chemicals.

Biological significance

Many biologically important molecules contain the amine functional group, including amino acids, which are the building blocks of proteins. Amines are also found in neurotransmitters such as dopamine and serotonin, which are important for nerve function in humans and animals.

Summary

In summary, amines are versatile and essential compounds in organic chemistry. They are characterized by their nitrogen-containing functional group and are classified into primary, secondary, and tertiary amines based on their substitution level. Amines are important in a variety of chemical reactions, industrial applications, and biological processes, making them an integral part of both chemical and life sciences.


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Amin

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