Hydroxyl

Question 1

Preparation

Answer 1

1. From alkenes via E.A.
   - cold,conc H2SO4 (lab)
   - H2O warm (lab)
   - H3PO4, high temp, high pressure (industry)
2. From halogenoalkanes via Nu:sub
   - NaOH, heat
3. Reduction of primary alcohols
   - C.A.
   a) LiAlH4 in dry ether
   -Aldehyde
   a) LiAlH4 in dry ether/ H2/Ni catalyst heat/ NaBH4 in methanol
4. Reduction of secondary alcohols
   -Ketone
   a) LiAlH4 in dry ether/ H2/Ni catalyst heat/ NaBH4 in methanol

Question 2

Oxidation

Answer 2

1. Primary alcohols
   - aldehydes
   a)H2SO4(aq), K2Cr2O7(aq)/ heat with immediate distillation

-carboxylic acids
a) H2SO4(aq), KMnO4(aq)/K2Cr2O7(aq)/ heat with reflux

2. Secondary alcohols
   -ketones
   a) H2SO4(aq), KMnO4(aq)/K2Cr2O7(aq) heat

3.Tertiary alcohols
-do not undergo oxidation

Question 3

Elimination

Answer 3

Alcohols undergo elimination to form alkenes
- excess conc H2SO4, heat
- Al2O3, heat

Question 4

Physical properties

Answer 4

1. Polar and can dissolve easily in water due to formation of H bonds
2. MP and BP affected by
   - degree of branching
   - size of electron cloud
   - extensiveness of H bonding

Question 5

Reactions

Answer 5

1. Nu:sub forming halogenoalkanes
   - dry HX(g)
   -PCl3 anhydrous , heat
   -PCl5 (anhydrous)
   -SOCl2(anhydrous)
2. Nu:sub condensation forming esters (R-O-CR’=O)
   - acyl chloride (RCOCl), r.t.
   - conc H2SO4, heat, C.A.
3. Redox
   -Na metal to form (O-Na+)
4. Alkoxide oxidation (-CHOHCH3 /CHOHCH2I /CHOHCHI2 /CHOHCI3 )
   - Iodoform test forming CHI3 (yellow ppt), carboxylate salt) and water
   a) I2(aq), NaOH (aq), warm