1. Chemistry 2100
Chapter 14

2. ALCOHOLS
ETHERS
THIOLS

3. alcohol
ether
thiol / mercaptan
(sulfhydryl)

4. Common Nomenclature
IUPAC Nomenclature
• dialkyl "ether"
• alkyl "alcohol"
• "e" "ol"
• locator numbers

5. Alcohols
Alcohol: A compound that contains an -OH (hydroxyl) group bonded to a tetrahedral carbon.
Methanol, CH3OH, is the simplest alcohol.
Nomenclature
1. Select the longest carbon chain that contains the -OH group as the parent alkane and number it from the end that gives the -OH the lower number.
2. Change the ending of the parent alkane from -e to -ol and use a number to show the location of the -OH group; for cyclic alcohols, the carbon bearing the -OH group is carbon-1.
3. Name and number substituents and list them in alphabetical order.

6. Nomenclature
In the IUPAC system, a compound containing two hydroxyl groups is named as a diol, one containing three hydroxyl groups as a triol, and so forth.
IUPAC names for diols, triols, and so on retain the final "-e" in the name of the parent alkane.
We commonly refer to compounds containing two hydroxyl groups on adjacent carbons as glycols.

7. Physical Properties Alcohols are polar molecules.
The C-O and O-H bonds are both polar covalent.

8. Physical Properties
In the liquid state, alcohols associate by hydrogen bonding.

9. boiling points (°C)
CH3OH ° CH3CH2CH2OH °
CH3CH ° CH3CH2CH2CH °
CH3Cl ° CH3CH2CH2Cl °
PhOH ° CH3CH2CH2CH2OH °
PhCH ° (CH3)2CHCH2OH °
PhCl ° (CH3)3COH °

10. solubility (g / 100 mL H2O)
CH3CH2OH
CH3CH2CH2OH
CH3CH2CH2CH2OH
CH3CH2CH2CH2CH2OH
CH3CH2CH2CH2CH2CH2OH
CH3CH2CH2CH2CH2CH2CH2CH2OH
CH3CH2OCH2CH3
(CH3)2CHCH2OH
(CH3)3COH
C6H11OH ∞
8.3
2.4
0.6
0.05
7.8
10.0
3.6

11. Acidity of Alcohols Alcohols have about the same pKa values as water.
Aqueous solutions of alcohols have the same pH as that of pure water.
Alcohols and phenols both contain an OH group.
Phenols are weak acids and react with NaOH and other strong bases to form water-soluble salts.
Alcohols are weaker acids than phenols and do not react in this manner. n

12. Preparing Alcohols Fermentation Alkene Hydration H H H H H H H H
zymase
sucrose
ethanol
Alkene Hydration H H H H H H H H

13. Dehydration

14. Oxidation of Alcohols
(1°)
(2°)

23. Ethers

24. Common Nomenclature
IUPAC Nomenclature
• dialkyl "ether"
• dialkyl "ether"
• "alkoxy"

25. Physical Properties
Ethers are polar molecules in which oxygen bears a partial negative charge and each carbon bonded to it bears a partial positive charge.

26. Physical Properties
However, only weak forces of attraction exist between ether molecules in the pure liquid.
Consequently, boiling points of ethers are close to those of hydrocarbons of similar molecular weight.
Ethers have lower boiling points than alcohols of the same molecular formula.

27. Reactions of Ethers
Ethers resemble hydrocarbons in their resistance to chemical reaction.
They do not react with oxidizing agents such as potassium dichromate.
They do not react with reducing agents such as H2 in the presence of a transition metal catalyst or with hydride reducing agents such as NaBH4.
They are not affected by most acids or bases at moderate temperatures.
Because of their general inertness and good solvent properties, ethers, such as diethyl ether and THF, are excellent solvents in which to carry out organic reactions.

28. pentane
bp 36°C
(diethyl) ether
bp 36°C
7.8 g/100 mL
1-butanol
bp 118°C
8.3 g/100 mL

29. Anesthetics

30. p. 409

31. Thiols

32. Thiols Thiol: A compound containing an -SH (sulfhydryl group).
The most outstanding property of low-molecular-weight thiols is their stench.
They are responsible for smells such as those from rotten eggs and sewage.
The scent of skunks is due primarily to these two thiols.

33. Naming thiols
Alkane + thiol
1-propanethiol
2-propene-1-thiol

34. Physical Properties
Because of the small difference in electronegativity between sulfur and hydrogen ( = 0.4), an S-H bond is nonpolar covalent.
Thiols show little association by hydrogen bonding.
Thiols have lower boiling points and are less soluble in water and other polar solvents than alcohols of similar molecular weight.

35. CH3CH2OH (bp 78°C) CH3OCH3 (bp -24°C)
CH3CH2SH (bp 35°C) CH3SCH3 (bp 37°C)

36. Oxidation
sulfide (thioether)
sulfoxide
sulfone

37. cysteine

42. -helix

43. -helix
-helix

44. -helix
-helix

45. -helix
-helix

46. -helix
-helix
-pleated sheet

47. -pleated sheet
-helix
-helix
-pleated sheet

48. -pleated sheet
-helix
salt bridge
-helix
-pleated sheet

49. -pleated sheet
-helix
salt bridge
-helix
hydrogen
bond
-pleated sheet

50. -pleated sheet
-helix
hydrogen
bond
salt bridge
-helix
hydrogen
bond
-pleated sheet

51. hydrophilic
interaction
to water
-pleated sheet
-helix
hydrogen
bond
salt bridge
-helix
hydrogen
bond
-pleated sheet

52. hydrophilic
interaction
to water
-pleated sheet
-helix
hydrogen
bond
hydrophobic
interaction
salt bridge
-helix
hydrogen
bond
-pleated sheet

53. hydrophilic
interaction
to water
-pleated sheet
-helix
hydrogen
bond
hydrophobic
interaction
salt bridge
-helix
hydrogen
bond
-pleated sheet

54. hydrophilic
interaction
to water
-pleated sheet
-helix
hydrogen
bond
hydrophobic
interaction
salt bridge
disulfide
bond
-helix
hydrogen
bond
-pleated sheet