Esters, Alcohols, and Carboxylic Acids

Alcohols

Functional Group

• OH (Hydroxyl group)
• Important for drawing display formulas: H forms 1 bond, C forms 4 bonds, O forms 2 bonds

Naming Alcohols

• Mnemonic: Monkeys Eat Peanut Butter (Helps remember prefixes)
  • Monkeys = Meth
  • Eat = Eth
  • Peanut = Prop
  • Butter = But
• All alcohols end in -ol

Examples

1. Methanol

   • Molecular formula: CH₄O
   • Prefix: Meth-
   • Structure: Draw OH group, then add hydrogens

2. Ethanol

   • Molecular formula: C₂H₆O
   • Prefix: Eth-
   • Found in alcoholic drinks

3. Propanol

   • Molecular formula: C₃H₈O
   • Prefix: Prop-
   • Propan-1-ol: OH group on first carbon
   • Propan-2-ol: OH group on second carbon
   • Both are isomers (same molecular formula, different displayed formulae)

4. Butanol

   • Molecular formula: C₄H₁₀O
   • Prefix: But-
   • Butan-1-ol: OH group on first carbon
   • Butan-2-ol: OH group on second carbon
   • Only two possible isomers for butan-1-ol and butan-2-ol

Carboxylic Acids

Functional Group

• COOH (Carboxyl group)
• All names end in -anoic acid

Examples

1. Methanoic Acid

   • Prefix: Meth-
   • Functional group: COOH

2. Ethanoic Acid

   • Prefix: Eth-
   • Functional group: COOH

3. Propanoic Acid

   • Prefix: Prop-
   • Functional group: COOH

4. Butanoic Acid

   • Prefix: But-
   • Functional group: COOH

Esters

Formation

• Esters are formed when an alcohol reacts with a carboxylic acid
• Reaction is reversible and produces water (H₂O) as a byproduct
• Example of a condensation reaction (small molecule like water is released)
• Requires a catalyst (typically strong sulfuric acid)
• Functional group: RCOOR'

Naming Esters

1. Methanol + Ethanoic Acid

   • Ester formed: Methyl Ethanoate
   • First part from alcohol: Methyl-
   • Second part from carboxylic acid: -ethanoate

2. Ethanol + Propanoic Acid

   • Ester formed: Ethyl Propanoate
   • First part from alcohol: Ethyl-
   • Second part from carboxylic acid: -propanoate

Properties of Esters

• Sweet-tasting and smelling
• Volatile (evaporate easily)
• Used in food flavorings and fragrances