1. 1 National 5 Chemistry Alcohols

2. 2 An alcohol contains  A hydroxyl group (—OH) attached to a carbon chain.

3. 3 Alcohols are classified  By the number of alkyl groups attached to the carbon bonded to the hydroxyl.  As primary (1°), secondary (2°), or tertiary (3°). Primary (1º) Secondary (2º) Tertiary (3º) 1 group 2 groups 3 groups H CH 3 CH 3 | | | CH 3 —C—OH CH 3 —C—OH CH 3 —C—OH | | | H H CH 3 Classification of Alcohols

4. 4 Classify each alcohol as (P) primary, (S) secondary, or (T) tertiary. OH | 1. CH 3 —CH—CH 2 —CH 3 2. CH 3 —CH 2 —CH 2 —OH OH | 3. CH 3 —CH 2 —C—CH 2 —CH 3 | CH 3 Learning Check

5. 5 Naming Alcohols The names of alcohols  In the IUPAC system replace -e of alkane name with - ol.  that are common names use the name of the alkyl group followed by alcohol. FormulaIUPACCommon Name CH 4 methane CH 3 ─OH methanol methyl alcohol CH 3 ─CH 3 ethane CH 3 ─CH 2 ─OH ethanol ethyl alcohol

6. 6 More Names of Alcohols In IUPAC names for longer carbon chains, the chain is numbered from the end nearest the ─OH group. CH 3 ─CH 2 ─CH 2 ─OH propan-1-ol OH │ CH 3 ─CH─CH 2 ─CH 3 butan-2-ol CH 3 OH │ CH 3 ─CH─CH 2 ─CH 2 ─CH─CH 3 5-methyl hexan-2-ol 6 5 4 3 2 1

7. 7 Some Typical Alcohols OH | “rubbing alcohol”CH 3 —CH—CH 3 2-propanol (isopropyl alcohol) antifreeze HO—CH 2 —CH 2 —OH 1,2-ethanediol (ethylene glycol) OH | glycerolHO—CH 2 —CH—CH 2 —OH 1,2,3-propanetriol

8. 8 Learning Check Give the IUPAC name for each of the following: 1. CH 3 —CH 2 —CH 2 —CH 2 —OH OH CH 3 | | 2. CH 3 —CH—CH—CH 2 —CH 3 3.

9. 9 Write the structure of the following: A. 3-pentanol B. ethyl alcohol C. 3-methylcyclohexanol Learning Check

10. 10 Physical Properties of Alcohols

11. 11 Boiling Points of Alcohols Alcohols  Contain a strongly electronegative O in the OH groups.  Form hydrogen bonds between alcohol molecules.  Have higher boiling points than alkanes and ethers of similar mass.

12. 12 Solubility of Alcohols in Water  Alcohols are more soluble in water than alkanes because the oxygen atom hydrogen bonds with water.  Alcohols with 1-4 C atoms are soluble, but alcohols with 5 or more C atoms are not.

13. 13 Comparing Solubility and Boiling Points CompoundMolarBoiling Soluble Mass Point (°C) in Water? Alkane CH 3 ─CH 2 ─CH 3 44-42 No Ether CH 3 ─O─CH 3 46-23 Yes Alcohol CH 3 ─CH 2 ─OH 46 78 Yes

14. 14 Learning Check Which compound would be more soluble in water? Explain. ethanol or 2-pentanol

15. 15 Reactions of Alcohols

16. 16 Combustion of Alcohols Combustion is the reaction of an alcohol with O 2 to produce CO 2 and H 2 O. 2CH 3 OH + 3O 2 2CO 2 + 4H 2 O + Heat

17. 17 Dehydration of an alcohol occurs  When heated with an acid catalyst.  With the loss of —H and —OH from adjacent carbon atoms. H OH | | H +, heat H—C—C—H H—C=C—H + H 2 O | | H H H H alcohol alkene Dehydration of Alcohols

18. 18 Learning Check Write the equations for the reactions when 2-propanol undergoes: 1. combustion 2. dehydration

19. 19 Oxidation and Reduction In the oxidation of an organic compound  There is an increase in the number of C—O bonds.  There is a loss of H. In the reduction of an organic compound  There is an decrease in the number of C—O bonds.  There is a gain of H.

20. 20 Oxidation and Reduction

21. 21 Oxidation of Ethanol in the Body In the body,  Ethanol is oxidized by enzymes in the liver.  Aldehyde product impairs coordination. O ║ ║ CH 3 ─CH 2 ─OH CH 3 ─C─H CH 3 ─C─OH Ethanol acetaldehyde acetic acid 2CO 2 + H 2 O

22. 22 Ethanol  Acts as a depressant.  Kills or disables more people than any other drug.  Is metabolized at a rate of 12-15 mg/dL per hour by a social drinker.  Is metabolized at a rate of 30 mg/dL per hour by an alcoholic. Ethanol CH 3 ─CH 2 ─OH

23. 23 Effect of Alcohol on the Body TABLE 13.2