Hydroboration Oxidation Lab

Overview

• The video covers:
  • The reaction of converting one-octane to one-octanol.
  • Discussion on Markovnikov vs. anti-Markovnikov reactions.
  • Review of Lewis acids and bases.
  • Details of the experimental procedure.
  • Carbon NMR analysis.

Reaction Details

• Steps Involved:
  1. Hydroboration:
     • Reaction with one-octane using borane (BH3) THF complex.
  2. Oxidation:
     • Converts the alkyl borane to alcohol using hydrogen peroxide.
• Anti-Markovnikov Reaction:
  • Addition occurs at the less substituted carbon of the alkene.

Lewis Acid-Base Chemistry

• Lewis Acids: Electron acceptors.
• Lewis Bases: Electron donors.
• Example:
  • Borane as a Lewis acid due to an empty p orbital.

Hydroboration Step

• Reagents: BH3 THF complex.
• Safety:
  • Use dry glassware to avoid water reaction.
  • Use a drying tube with calcium chloride.
  • Conduct in ventilated hood.
• Procedure:
  • Chill reaction vessel in ice bath.
  • Add reagents dropwise to control reactivity.

Oxidation Step

• Reagents: Hydrogen peroxide and sodium hydroxide.
• Procedure:
  • Add hydrogen peroxide dropwise.
  • Allow to reflux for about an hour.

Product Extraction

• Solvent: Ethyl ether for organic layer separation.
• Washing: HCl to remove residual base.
• Drying: With sodium sulfate.

Product Purification

• Method: Plug chromatography.
• Materials: Silver nitrate treated silica gel.

Experimental Setup

• Apparatus:
  • Conical vial, Claisen head adapter, drying tube.
  • Use a needle and syringe for reagent handling.
• Refluxing and Reaction:
  • Control temperature and reaction rate with an ice bath.

NMR Analysis

• HMR:
  • Identify overlapping peaks.
• Carbon NMR:
  • Analyze peaks for molecule confirmation.
  • Compare with reference molecules for peak assignments.

Key Points

• Proper handling of reactive borane compounds is crucial for safety.
• Silver nitrate aids in separating product from contaminants.
• NMR analysis provides confirmation of molecular structure and purity.

Conclusion

• Successfully produced one-octanol, though some contamination was noted.
• Techniques used are essential for ensuring the successful completion of organic synthesis reactions.