1. Chapter 7- Alcohols

2. Alcohols- commercially important Ethanol CH 3 CH 2 OH - Produced by fermentation or hydration of ethylene CH 2 =CH 2 + H 2 O H 2 SO 4 CH 3 -CH 2 OH Commercial EtOH 95% H 2 O 5% Can’t purify further by distillation To remove water Absolute alcohol use CaO CaO + H 2 OCa(OH) 2 Ethanol- Solvent, fuel, antiseptic, reagent

5. Covalent OH bond ~ 480 kJ mol -1 Hydrogen bond ~ 20-40 kJ mol -1 Much weaker but has important effects (i)Boiling points of alcohols are higher than would be predicted based on molecular weight -Extra energy required to break the intermolecular hydrogen bonds (ii) Lower molecular weight alcohols are soluble in water CH 3 CH 2 OH CH 3 OCH 3 CH 3 CH 2 CH 3 MW 46 46 44 B.P. +78.5 o C -24 o C -42 o C

6. Preparation of Alcohols (i) Reduction of aldehydes, ketones, carboxylic acid derivatives (ii) Addition of H 2 O to an alkene e.g. oxymercuration

7. Intermolecular Hydrogen Bonding

8. Alcohols are weak acids

9. 7.8 Dehydration of alcohols- alkenes - Occurs by heating with a strong acid

11. Mechanism of dehydration

12. 7.9 Reaction of Alcohols with Hydrogen Halides

18. Thiols: S (sulfur) analogues of alcohols