1. Chapter 14 Alcohols, Phenols, Ethers, and Thiols
14.5 Physical Properties of Alcohols, Phenols, and Ethers
14.6 Reactions of Alcohols

2. Boiling Points of Alcohols
Alcohols contain a strongly electronegative O in the OH groups.
Thus, hydrogen bonds form between alcohol molecules.
Hydrogen bonds contribute to higher boiling points for alcohols compared to alkanes and ethers of similar mass.

3. Boiling Points of Ethers
Ethers have an O atom, but there is no H attached.
Thus, hydrogen bonds cannot form between ether molecules.

4. Solubility of Alcohols and Ethers in Water
Alcohols and ethers are more soluble in water than alkanes because the oxygen atom can hydrogen bond with water.
Alcohols with 1-4 C atoms are soluble, but alcohols with 5 or more C atoms are not.

5. Reactions of Alcohols
Alcohols undergo combustion with O2 to produce CO2 and H2O.
2CH3OH + 3O CO H2O + Heat
Dehydration removes H- and -OH from adjacent carbon atoms by heating with an acid catalyst.
H OH
| | H+, heat
H—C—C—H H—C=C—H + H2O
| | | |
H H H H
alcohol alkene

6. Formation of Ethers
Ethers form when dehydration takes place at low temperature. H+
CH3—OH + HO—CH CH3—O—CH3 + H2O
Two Methanol Dimethyl ether

7. Oxidation and Reduction
In organic chemistry, oxidation is a loss of hydrogen atoms or a gain of oxygen.
In an oxidation, there is an increase in the number of C-O bonds.
Reduction is a gain of hydrogen or a loss of oxygen. The number of C-O bonds decreases.

8. Oxidation of Primary Alcohols
In the oxidation [O] of a primary alcohol, one H is lost from the –OH and another H from the carbon bonded to the OH.
[O]
Primary alcohol Aldehyde
OH O
| [O] ||
CH3—C—H CH3—C—H + H2O | H
Ethanol Ethanal
(ethyl alcohol) (acetaldehyde)

9. Oxidation of Secondary Alcohols
The oxidation of a secondary alcohol removes one H from –OH and another H from the carbon bonded to the –OH.
[O]
Secondary alcohol Ketone
OH O
| [O] ||
CH3—C—CH CH3—C—CH3 + H2O | H
2-Propanol Propanone
(Isopropyl alcohol) (Dimethylketone; Acetone)

10. Oxidation of Tertiary Alcohols
Tertiary alcohols are resistant to oxidation. [O]
Tertiary alcohols no reaction OH
| [O]
CH3—C—CH3 no product |
CH no H on the C-OH to oxidize
2-Methyl-2-propanol

11. Ethanol CH3CH2OH Ethanol: Acts as a depressant.
Kills or disables more people than any other drug.
Is metabolized at a rate of mg/dL per hour by a social drinker.
Is metabolized at a rate of 30 mg/dL per hour by an alcoholic.

12. Oxidation of Alcohol in the Body
Enzymes in the liver oxidize ethanol.
The aldehyde produced impairs coordination.
A blood alcohol level over 0.4% can be fatal O || CH3CH2OH CH3CH CO2 + H2O Ethyl alcohol acetaldehyde

13. Oxidation of alcohols in liver

14. Effect of Alcohol on the Body

15. Breathalyzer test K2Cr2O7 (potassium dichromate)
This orange colored solution is used in the Breathalyzer test (test for blood alcohol level)
Potassium dichromate changes color when it is reduced by alcohol
K2Cr2O7 oxidizes the alcohol

16. Breathalyzer reaction
orange-red green
8H++Cr2O72-+3C2H5OH→2Cr3++3C2H4O+7H2O
dichromate ethyl chromium (III) acetaldehyde
ion alcohol ion
(from K2Cr2O7)

17. Alcohol Contents in Common Products
% Ethanol Product
50% Whiskey, rum, brandy
40% Flavoring extracts
15-25% Listerine, Nyquil, Scope
12% Wine, Dristan, Cepacol
3-9% Beer, Lavoris

18. The proof of an alcohol
The proof of an alcoholic beverage is merely twice the percentage of alcohol by volume.
The term has its origin in an old seventeenth-century English method for testing whiskey.
Dealers were often tempted to increase profits by adding water to booze.
A qualitative method for testing the whiskey was to pour some of it on gunpowder and ignite it.
If the gunpowder ignited after the alcohol had burned away, this was considered “proof” that the whiskey did not contain too much water.

19. Production of ethanol from grain by fermentation
Grain seeds are grounded and cooked → mash
Malt (the dried sprouts of barley) or special mold is added → source of the enzyme diastase that catalyzes the conversion of starch to malt sugar, maltose
diastase
(C6H10O5)2x + H2O → x C12H22O11
starch maltose
Pure yeast culture is added
C12H22O11 + H2O → 2 C6H12O6
maltose glucose
C6H12O6 → 2 CH3CH2OH + 2 CO2
glucose ethanol carbon dioxide

20. Preparation of alcohols
Ethanol is made by hydration of ethylene (ethene) in the presence of acid catalyst

21. Isopropyl
is produced by addition of water to propylene (1-propene)

22. Methanol is made commercially from carbon monoxide and hydrogen
CO + 2H2 → CH3OH

23. Oxidation of Thiols.
Mild oxidizing agens remove two hydrogen atoms from two thiol molecules.
The remaining pieces of thiols combine to form a new molecule, disulfide, with a covalent bond between two sulfur atoms.
R – S – H H – S – R+I2 → RS – SR+2HI
2 RSH + H2O2 → RS – SR + 2 H2O

24. The chemistry of the “permanent” waving of hair.
Hair is protein, and it is held in shape by disulfide linkages between adjacent protein chains.
The first step involves the use of lotion containing a reducing agent such as thioglycolic acid, HS – CH2 – COOH.
The wave lotion ruptures the disulfide linkages of the hair protein.
The hair is then set on curles or rollers and is treated with a mild oxidizing agent such as hydrogen peroxide (H2O2).
Disulfide linkages are formed in new positions to give new shape to the hair.
Exactly the same chemical process can be used to straighten naturally curly hair.
The change in hair style depends only on how one arranges the hair after the disulfide bonds have been reduced and before the reoxidation takes place.
Permanent Hair Wave (