Ch 12 Alcohol & Thiol

1. Ch 12 Alcohol & Thiol Reactions

2. Dehydration of Alcohol • An –H and an –OH of adjacent carbon atoms are removed to form and alkene and water • Heat and an acid catalyst are needed

3. Oxidation of Alcohol • Oxidation – loss of H atoms or gain of O2 atoms • Oxidation occurs when there is an increase in the number of C-O bonds • In a reduction, the product has fewer bonds between carbon and oxygen

4. Oxidation of Primary Alcohol • Primary alcohol produces and aldehyde • Removes 2 –H atoms (1 –H from the –OH and 1 –H from the carbon bonded to the –OH) • Use the symbol [O] to show oxidizing agent

5. Oxidation of Primary Alcohol • Aldehyde oxidizes further with the addition of another O2 to form carboxylic acid • Very fast reaction…not easily isolated in a lab

6. Oxidation of Secondary Alcohol • Secondary alcohols produce ketones • Removes 1 –H atom from –OH and 1 –H atom from the carbon bonded to the –OH

7. Oxidation of Secondary Alcohol • Tertiary alcohols do not oxidize • No –H on carbon bonded to –OH • C-C bonds too strong to oxidize

8. Oxidation of Thiols • Thiols undergo oxidation by a loss of –H from the –SH group (more than 1 thiol molecule must be present) • Oxidized product is called a disulfide • Factoid – protein in hair is cross-linked by disulfide bonds • In a ‘perm’…these bonds are broken and then oxidized while in the rollers so hair forms disulfide bonds in a new shape

9. Homework Page 399 (12.18 and 12.20)