Lecture on Esters

Introduction to Esters

• Esters: Chemical compounds used to provide artificial scents.
• Commonly found in products like perfumes, lotions, gums, and more.

Characteristics of Esters

• Known for fruity or sweet smells.
• Examples:
  • Methyl salicylate (peppermint smell)
  • Hexanoate, Heptanoate (pepperminty scents)
  • Other scents include coconut, floral, oranges, etc.

Uses of Esters

• Artificial Scents: Used in consumer products that are not naturally grown (e.g., perfumes, lotions, candles).
• Food Products: Often prefer naturally sourced scents.

Industry Debate

• Discussion around artificial vs. natural scents:
  • Artificial scents are lab-made by combining alcohols and carboxylic acids.
  • Natural scents are extracted from sources like fruit peels.
• Concerns about ingesting vs. skin absorption of artificial products.

Chemical Reaction - Making Esters

• Condensation Reaction: Process of creating esters by mixing alcohol with a carboxylic acid.
• Important details:
  • Too much alcohol can make the ester smell like a cleaner.
  • Too much acid can give a rancid smell.

Reaction Mechanism

• A delicate balance between alcohol and acid is necessary.
• Reaction removes H from alcohol and OH from acid to form water.
• The remaining oxygen and carbon atoms form the ester.

Example Reaction

• Methanol (alcohol) + Butanoic Acid (acid) → Methyl Butanoate (ester)
• Naming:
  • Alcohol ends in 'ol', changes to 'yl' (e.g., Methanol to Methyl).
  • Acid ends in 'ic', changes to 'ate' (e.g., Butanoic to Butanoate).

Educational Context

• Previously done as a lab experiment but discontinued due to safety concerns (hexane solvent).
• Future assignments may include similar exercises.