Haloalkanes and Haloarens Lecture
Introduction
- Haloalkanes: When a halogen (fluorine, chlorine, bromine, iodine) is bonded with an alkane.
- Haloarens: When halogen is bonded with an aromatic compound.
Topics
- Structure and Nomenclature
- How to construct and name haloalkanes.
- Example: Chloromethane.
- Preparation
- Making haloalkanes from alkanes.
- Changes during reaction.
- Free radical substitution process.
- Preparation from alcohols.
- Properties
- Physical properties like color, state, and comparison with hydrocarbons.
- Boiling point and density.
- Solubility.
Detailed Topics
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Structure and Nomenclature
- Naming examples of haloalkanes:
- Chloro propane
- Bromo propane
- Propyl chloride
- IUPAC and common naming.
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Preparation
- Free Radical Substitution:
- Formation of haloalkanes with chlorine.
- Chlorination of methane.
- Preparation from Alcohol:
- Use of PCl5, PCl3.
- Use of silver salts.
- Wurtz Reaction: Reaction of haloalkane with sodium.
- Formation of Aromatic Group: Formation of haloarens.
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Properties
- Physical Properties:
- Haloalkanes are generally colorless.
- Boiling point, density: Haloalkanes have higher boiling points and density than normal hydrocarbons.
- Boiling point comparison in isomers.
- Solubility:
- Slightly soluble in polar solvent.
- More soluble in non-polar solvent.
Important Reactions and Rules
- Markovnikov's Rule: Negative part attaches where there are fewer hydrogen atoms.
- Free-radical Mechanism: Steps of the reaction.
- Addition Reaction: Use of hydrogen chloride.
- Distinction in Haloalkanes: Mono, di, tri halo alkanes.
- Partition Point: Making haloalkane from alkane.
Applications
- Use of haloalkanes as industrial disinfectants, medicinal compounds, and synthetic fibers.
- Natural compounds: Use of iodine in thyroxine hormone.
- Medical use: In anesthesia, chloroform, and other drugs.
Conclusion
Studying haloalkanes and haloarens helps in understanding chemical reactions, their applications, and their importance.