Alcohols, Phenols, and Ethers

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Chapter 14

• Alcohols, Phenols, and Ethers

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Bonds to Oxygen
So, to review
Carbon forms 4 bondsHydrogen forms 1
bond.oxygen forms 2 bonds
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Alcohols

• Contain HYDROXYL functional group (-OH) bonded to
  saturated carbon atom
• Think of as
• Alkyl derivative of H2O
• Or
• Hydroxyl derivative of alkane

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Nomenclature

• Find longest chain that contains OH
• Change e to ol in alkane
• Numbering begins at end nearest OH
• -OH takes precedence over double and triple bonds
  (Oxygen has higher atomic weight)
• 2 OH groups diol
• 3 OH groups triol

3-ethyl-4-methyl-2-heptanol
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Give IUPAC names for the following alcohols
2, 5-dimethyl-3-heptanol
3-methylcyclohexanol
1-butanol
4-methyl-5-hepten-2-ol
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Some Common Alcohols

• Methanol (methyl alcohol)
• Racing fuel
• Solvent
• Formed from CO H2
• Toxic Oxidized in liver to formaldehyde
• Ethanol (ethyl alcohol)
• Beverages
• Formed naturally by yeast (fermentation) and
  industrially from ethene H2O
• Oxidized in liver to acetaldehyde (hangover!)
• 2-propanol (isopropyl alcohol)
• Rubbing alcohol
• Toxic Converted in liver to acetone
• 1,2 ethanediol (ethylene glycol)
• Antifreeze
• Toxic Converted in liver to oxalic acid (kidney
  stones!)
• 1, 2, 3-propantriol (glycerol)
• Base of triglycerides

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Physical Properties

• Alcohols contain polar (OH) and non-polar (alkyl)
  groups

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• Fig. 14.8
• (a) Boiling points and (b) solubilities in water
  of selected 1- alcohols.

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Physical properties
H-bonds

• Hydrogen bonds between water and alcohol
• increase solubility in water
• raise boiling points

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Alcohols are classified as primary, secondary, or
tertiary (1, 2, 3)

• How many carbons is hydroxyl carbon bonded to?

2
1
3
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Alcohol Reactions

• Combustion
• CxHyOH O2 ? CO2 H2O
• Intramolecular Dehydration
• Removal of water (This is the reverse of
  HYDRATION!)

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Alcohol Reactions, continued

• Zaitsevs Rule The double bond goes between the
  MOST SUBSTITUTED CARBONS

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Alcohol Reactions, continued

• Intermolecular Dehydration
• Condensation reaction 2 molecules join to form 1
  larger molecule with production of water
• For alcohols
• Alcohol 1 Alcohol 2 ? ETHER

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Alcohol Reactions, continued

• Oxidation
• Loss of electrons or
• Loss of hydrogens or
• Gain of oxygen (increase in number of bonds to
  oxygen

Reduction
Reduction is opposite
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Oxidation of alcohols, continued
Primary alcohol
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Oxidation of alcohols, continued

• Secondary alcohol oxidation
• 2 alcohol ? ketone

Tertiary alcohols CANNOT be oxidized! (Why not?)
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Phenols
3-chlorophenol (m-chlorophenol)
Phenol
2, 5-dibromophenol
4-ethyl-2-methylphenol
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Practical Implications
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Ethers Nomenclature
R-O-R

• Usually called by common name
• Alkoxy-
• CH3-O-CH2-CH3
• 1-methoxyethane (IUPAC name)
• Or
• Name both alkanes, then ether
• Ethyl methyl ether (common name)

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Summary of Physical Properties

• Alcohols (including phenols) are more soluble in
  water than corresponding alkane (or ether)
• BUT
• The LONGER the carbon chain, the LESS soluble
  Non-polar carbon atoms make molecule non-polar
• Alcohols have HIGH boiling points.

Both properties stem from H-bonding
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Physical Properties of Ethers

• Fig. 14.19
• A physical-state summary for unbranched alkyl
  ethers at room temperature and pressure.

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Sulfur-Containing Organic Compounds

• ThioethersThiols, disulfides, and thioethers

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Thiol nomenclature Replace ol ending with
thiol
Thiol thiol ? DISULFIDE
Thioether Replace O with S R-S-R (Sulfide)