Fats and Oils in Higher Chemistry

Introduction

• Esters: Formed in condensation reactions, broken by hydrolysis.
• Fats and Oils: Naturally occurring esters, crucial in diets.

Importance of Fats and Oils

• Provide energy.
• Transport vitamins soluble in fats.
• Sourced from plants (e.g., sunflower oil, palm oil) and animals (e.g., lard, cod liver oil).

Structure of Fats and Oils

• Composition: Esters formed from glycerol and long-chain carboxylic acids (fatty acids).
  • Glycerol: Also known as propane-1,2,3-triol, a triol with three hydroxyl groups.
  • Fatty Acids: Long chain (C4 to C28), saturated or unsaturated. Common examples include stearic acid and oleic acid.
• Fats and Oils: Known as triglycerides.
• Reaction: Reversible like other esters.

Physical Properties

• Oils: Liquids at room temperature, contain more C=C double bonds.
• Fats: Solids at room temperature, fewer C=C double bonds.
• Melting Points:
  • Oils have lower melting points due to higher unsaturation; C=C bonds distort shape, preventing close packing.
  • Fats pack closely due to less distortion, leading to higher melting points.

Chemical Reactions and Testing

• Hydrogenation: Increases melting point by reducing unsaturation, causing hardening.
• Bromine Test: Determines unsaturation level. More double bonds result in more bromine solution being decolorized.

Related Topics

• Systematic Carbon Chemistry
• Alcohols, Carboxylic Acids, Soaps, Detergents, Emulsions
• Proteins, Oxidation of Food, Fragrances, Skincare

External Resources

• BBC Science, BBC News: Science, SQA Higher Chemistry
• Royal Society of Chemistry, Creative Chemistry

These notes aim to summarize the key concepts regarding the chemistry of fats and oils, their structures, roles, and related chemical reactions, providing a foundational understanding for further study in organic chemistry.