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Week 15: Alcohols, Phenols and Ethers (Definition image (Alcohols…

- - - - named with the suffix “ol”
        
        Multiple –OH groups  …diol, …triol
        
        Steps
        
        Step 1: Find the LONGEST parent chain that contains the carbon bonded directly to the -OH group
        
        Step 2: Start numbering the carbon from the end that is NEARER to the –OH group (carbon bonded to –N group has the smallest possible number)
        
        Step 3: Identify the other substituents & positions. Arrange in alphabetical order
    - - Higher boiling point as compared to amines
        
        Due to presence of O and H, resulting in strong hydrogen bonding between alcohol molecules
        
        The longer the carbon chain, the higher the boiling point
        
        Due to presence of London Dispersion Forces between the alkyl groups
      - Solubility
        
        Hydrophilic: Alcohols with a total of < 5 carbon atoms in all the R groups soluble in water
        
        Hydrophobic: Alcohols with > 5 carbons
      - Viscosity
        
        As number of –OH group increases, viscosity increases as well
        (Less fluid)
      - Acidity & Basicity
        
        As weak acids, they can donate H+ ion to form alkoxide ion, RO-.
        
        As weak bases, they can accept H+ ion to form oxonium ion.
    - - Hydration of alkenes
        
        General Chem EQN:
        
        Reaction Mechanism
        
        Step 2: Generation of Carbocation. Produces MAJOR & MINOR products
        
        Step 3: Nucleophilic addition of H2O in BOTH major & minor products
        
        Step 4: Regeneration of H2SO4
      - Nucleophilic Substitution of alkyl halide
        
        Sn1 with Tertiary Alkyl halides
        
        Sn2 with Primary & Secondary Alkyl halides
      - Reduction of aldehydes or ketones
        
        By catalytic hydrogenation
        
        By Lithium aluminium hydride, LiAlH4
        
        By Grignard reagents
        
        Making the Grignard reagents
    - - SN1 reaction to form alkyl halide
      - Dehydration to form alkene
      - Oxidation of alcohols to form carbonyl compound
  - - - higher boiling points than alcohols
        
        strong hydrogen bonding and London Dispersion Forces between the molecules.
      - hygroscopic: absorbs moisture from environment
    - - Acid – Base Neutralization: Phenol are acidic
      - Electrophilic Substitution with Bromine water
    - - Sulphonation of benzene followed by alkali fusion
  - - - Williamson synthesis of ethers
        
        Step 1: Acid-Base Neutralization
        Alcohol (as weak acid) reacts with NaH (strong base) to form the sodium alkoxide.
        
        Step 2: SN2 Reaction
        Alkoxide ion (as nucleophile) attack alkyl bromide to form the ether.