Alcohol and phenol

• Alcohols contain a hydroxy group (OH) bonded to an sp³ hybridized carbon
• Classification of Alcohols

  • Primary alcohol
  • Secondary alcohol
  • Tertiary alcohol
• Compounds having a hydroxy group on a sp² hybridized carbon are called enols and phenols
• Alcohols


  Compounds with a hydroxy group (OH)
• Ethers and epoxides


  Contain the carbon-oxygen sigma bond
• Oxygen atom in alcohols, ethers, and epoxides


  Is sp³ hybridized
• Alcohols and ethers have a bent shape like that in H₂O
• The bond angle around the O atom in an alcohol or ether is similar to the tetrahedral bond angle of 109.5°
• The C—O and O—H bonds in alcohols are polar
• Nomenclature of Alcohols

  When an OH group is bonded to a ring, the ring is numbered beginning with the OH group
• The functional group is at C1, the 1 is usually omitted from the name
• Common names are often used for simple alcohols
• Diols


  Compounds with two hydroxy groups
• Triols


  Compounds with three hydroxy groups
• Alcohols have dipole-dipole interactions because they have a bent structure with two polar bonds
• Alcohols are capable of intermolecular hydrogen bonding
• Alcohols are polar
• Steric factors affect hydrogen bonding
• Ethanol is the alcohol in alcoholic beverages
• Sources for ethanol production

  • Wheat
  • Barley
  • Cassava
  • Grapes
  • Yam
  • Apples
  • Corn
  • Rice
  • Potatoes
  • Bananas
  • Plantains
• Manufacture of Alcohols

  1. From petroleum raw material

  2. By fermentation
• Manufacture of Methanol

  Passing hydrogen and carbon monoxide over a catalyst
• Manufacture of Ethanol by Fermentation

  Addition of yeast to raw material slurry
• Yeast contains biological catalysts called enzymes such as maltase and zymase
• Ethanol produced by fermentation must be properly distilled to remove primary alcohols and fused oil
• Methods of Preparation

  1. Direct hydration of alkenes

  2. Hydrolysis of alkyl halides

  3. Reduction of aldehydes, ketones, esters, and acids

  4. Using a Grignard reagent
• Hydrolysis


  Introduction of a hydroxyl group into a molecule
• Reducing agents can form corresponding alcohols
• LiAlH₄ and NaBH₄ reduce carbonyl groups without affecting carbon-carbon double bonds
• NaBH₄ is a milder reducing agent and will not reduce acids and esters
• Aldehydes and acids give primary alcohol
• Preparation of Alcohols using Grignard Reagent

  Reagents RMgX react with carbonyl compounds
• Chemical properties of alcohol

  Determined by its functional group -OH
• Alcohols show amphoteric behaviour, acting as acids and bases
• Methods of Preparation

  • Preparation of Alcohols
  • Using a Grignard Reagent
• Preparation of Alcohols using Grignard Reagent


  1. React Grignard reagents with carbonyl compounds

  2. Form organometallic intermediates

  3. Hydrolyse to alcohol
• Grignard Reagent


  • RMgX
  • Used for preparation of three classes of alcohols
• Synthesis of 1° Alcohols

  • Methanal and epoxide give primary alcohol
• Synthesis of 2° Alcohols

  • Alkanal gives Secondary alcohol
• Synthesis of 3° Alcohols

  • Ketone and Esters give Tertiary alcohol