MCAT Organic Chemistry: Alcohols

May 28, 2024

MCAT Organic Chemistry: Alcohols

Overview

  • Presenter: Iman
  • Channel: Iman's YouTube channel
  • Topic: Organic chemistry, focusing on alcohols
  • Context: Structured practice questions for MCAT preparation

Key Concepts

  • Boiling Points of Alcohols vs Hydrocarbons

    • Alcohols have higher boiling points due to hydrogen bonding
    • Trends to consider:
      • Intramolecular forces: Ionic > Hydrogen bonding > Dipole-dipole > Van der Waals
      • Boiling points increase with more carbons
      • Branching decreases boiling points
  • Oxidation of Alcohols

    • Tertiary alcohols oxidize with difficulty due to lack of hydrogen on the carbon
    • Definitions:
      • Reduction: Gain of electrons, formation of C-H bond, or loss of C-O bond
      • Oxidation: Loss of electrons, loss of C-H bond, or formation of C-O bond
  • IUPAC Nomenclature for Alcohols

    • Longest carbon chain determines the base name (e.g., Propane for 3 carbons)
    • Modifiers: Alcohol changes suffix to -ol or -diol for two alcohol groups
    • Proper numbering to give lowest position numbers to substituents
    • Example: 1,2-propanediol (1,2-propandiol)

Practice Problems and Solutions

  1. Boiling Points
  • Alcohols have higher boiling points due to hydrogen bonding (Answer: B)
  1. Oxidation of Tertiary Alcohols
  • Difficult due to lack of hydrogen on substrate carbon (Answer: No hydrogens available)
  1. Naming Alcohols
  • Longest chain and functional groups (Example: 1,2-propanediol)
  1. Boiling Points of Different Alcohols
  • Influenced by strength of intermolecular forces and carbon count
  • Example: Isobutyl alcohol > Propanol > Methanol (Answer: C)
  1. Acidity
  • Determined by stability of deprotonated form using ARIO (Atom, Resonance, Induction, Orbitals)
  • Phenol > Hexanol > Cyclohexanol (Answer: B)
  1. Conversion Reactions
  • Primary alcohol to aldehyde needs weak oxidizing agent like PCC (Answer: B)
  • Weak and strong agents convert secondary alcohol to ketone (Answer: D)
  1. Jones Oxidation
  • Requires oxidizing agent, solvent, and dilu sulfuric acid (Answer: A)
  1. Protecting Groups and Reactions
  • Methyl sulfonyl chloride acts as protecting group, no reaction with oxidizing agents (Answer: A)
  1. Ethylene Glycol Reaction
  • Forms hemi acetyl/keto (Answer: A)
  1. Oxidizing Agents for Alcohols
  • Primary alcohol with strong agent to carboxylic acid (Answer: D)

Conclusion

  • Recap of key concepts and practice problem solutions
  • Encouragement to reach out with questions or requests for specific problem walkthroughs
  • Closing wishes for good luck and successful studying

Additional Resources

  • Previous video playlist: opin102 for more detailed explanations on foundational concepts