Lecture Notes: Extraction Techniques in Organic Chemistry

Introduction to Perfumes

• Perfume creation involves isolating chemical compounds.
• Techniques like extraction are used to create various scents.

Extraction Process

• Extraction is a method used to separate chemical compounds.
• Key Equipment:
  • Separatory Funnel (Sep Funnel):
    • Top opening for pouring liquids.
    • Bottom stopcock to control liquid flow.
• Process:
  • Pour liquid mixture into the sep funnel.
  • Shake and allow the mixture to settle.
  • Two layers form due to different liquid densities.
    • Organic Phase: Contains uncharged species or neutral compounds.
    • Aqueous Phase: Contains water and charged species or ions.

How to Perform an Extraction

1. Open the stopcock.
2. Allow the aqueous phase to flow into the flask.
3. Close the stopcock, leaving the organic phase in the sep funnel.

Separation of Compounds

• Example 1: Hexane and Propanamine

  • Hexane is neutral; propanamine is basic.
  • Add an acid (e.g., HCl) to form a charged amino group in the aqueous layer.
  • Result: Hexane in organic layer, propanamine in aqueous layer.

• Example 2: Hexane and Phenol

  • Phenol is weakly acidic.
  • Add a base (e.g., NaOH) to form phenolate anion in the aqueous layer.
  • Result: Hexane in organic layer, phenol in aqueous layer.

Complex Extraction

• Example 3: Hexane, Phenol, and Acetic Acid
  • Use a milder base (e.g., sodium bicarbonate) for acetic acid.
  • Result: Acetate anion in aqueous layer; hexane and phenol in organic layer.
  • Further separation of phenol using NaOH to form phenolate anion.

Practical Tips

• Save each layer during extractions.
• Lost compounds can be recovered using multi-step extraction methods.

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These notes summarize the key points and processes involved in chemical extraction techniques used in organic chemistry, particularly for isolating and separating compounds based on their chemical properties.