Organic Chemistry - C7: Organic Compounds

Introduction to Organic Compounds

• Organic Compounds: Molecules with carbon as the backbone.
• Crude Oil: Found underground, composed mainly of hydrocarbons (carbon and hydrogen).
  • Alkanes: Chains of single covalently bonded carbon atoms with hydrogen.
  • General formula: ( C_nH_{2n+2} ).
  • Naming: Ends with "-ane"; prefix indicates carbon chain length (meth-1, eth-2, prop-3, etc.)._

Fractional Distillation

• Separates crude oil into fractions by boiling point differences.
• Fractionating Column: Heats crude oil, causing evaporation and condensation at different heights based on boiling points.
  • Shortest alkanes (LPG - up to 4 carbons) remain gaseous.
  • Other fractions: Petrol, kerosene, diesel oil, heavy fuel oil.
• Complete Combustion: Produces carbon dioxide and water.
• Properties:
  • Longer fractions: Higher boiling points, more viscous.
  • Shorter fractions: More flammable.

Uses of Fractions

• Fuels: LPG, petrol, kerosene, diesel.
• Other Uses: Solvents, lubricants, detergents, polymers (plastics).

Alkenes

• Alkenes: Hydrocarbons with carbon-carbon double bonds (( C=C )).
  • Unsaturated, react with bromine water to become colorless.
  • Produce polymers, different from alkanes.

Cracking

• Purpose: Meet demand for shorter alkanes and produce alkenes.
• Methods:
  • Catalytic Cracking: Uses zeolite catalyst, ~550°C.
  • Steam Cracking: No catalyst, >800°C.
• Example: Butane can crack into ethane and ethene.

Alcohols

• Alcohols: Organic compounds with ( -OH ) group.
  • Names end with "-ol" (e.g., ethanol).
  • Complete combustion produces carbon dioxide and water.
  • React with sodium to form sodium ethoxide and hydrogen.
  • Oxidation produces carboxylic acids (e.g., ethanoic acid).

Polymers

• Polymerization: Formation of long-chain molecules from monomers.
  • Addition Polymerization: Monomers with double bonds (e.g., ethene to polyethene).
  • Condensation Polymerization: Two monomers with functional groups, produces water (e.g., ethanol and ethanoic acid to polyester).

Biological Polymers

• Amino Acids: Building blocks of proteins, can form polypeptides.
• DNA: Double helix structure, composed of nucleotides.
• Starch and Cellulose: Natural polymers made from glucose.

Conclusion

• Organic chemistry involves understanding various compounds, their properties, uses, and methods of production.
• Important for applications in fuel production, material manufacturing, and biological processes.