Alcohols, Ethers

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Alcohols, Ethers Thiols

• Singly Bonded Oxygen

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Alcohols

• Structure
• Alcohols contain a hydroxyl group (-OH)
• Oxygen is sp3 hybridized, with bent geometry
• OH bond is polar, so smaller alcohols are soluble
  in water
• 1º, 2º, 3º Alcohols

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Alcohols
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Alcohol Nomenclature

• Suffix ol
• Gets numbering priority over double bonds
• Hydroxyl carbon must be numbered (C3 or higher)

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Nomenclature Physical Properties

• High boiling compared to similar MW alkanes due
  to hydrogen bonding
• Higher MW alcohols have higher MP/BP

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Physical Properties Reactions

• C1-C3 alcohols miscible with water
• Reactions of alcohols
• Acid catalyzed dehydration to alkenes

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Reactions

• Ease of dehydration 3ºgt2ºgt1º
• Mechanism ionic
• Water is a good leaving group

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Reactions

• Orientation of elimination Zaitsevs Rule
• Elimination will predominately give the most
  substituted alkene

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Reactions

• During double bond formation both carbons have a
  partial charge
• Oxidation to aldehydes and ketones
• Primary alcohols are oxidized to aldehydes
• Secondary alcohols are oxidized to ketones

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Reactions

• Rxn w/ acids ?esters

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Ethers

• Structure contain C-O-C group bent geometry
  like water
• Nomenclature
• Common names almost always used
• Name both groups attached to oxygen, and end both
  names in yl

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Ethers

• Common usage groups ranked in size order
• IUPAC OR is named as an alkoxy group
• CH3CH2OCH2CH3
• ethoxyethane (diethyl ether)
• Physical properties lower BP, less solubility
  in water than isomeric alcohols no H bonding
• Ethers are relatively inert

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Williamson ether synthesis
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Thiol structure and nomenclature

• Contain sulfydryl group (-SH)
• They are sulfur analogs of alcohols
• Sulfur is sp3 hybridized, with S-H bond angles of
  about 100º (big lone pairs)
• Nomenclature
• Suffix is thiol. The e of the parent carbon
  chain is not dropped.

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Thiol nomenclature

• Older name mercaptan
• CH3SH methyl mercaptan

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Thiol reactions

• Precipitation with mercury salts
• 2CH3SH Hg2 ? (CH3S)2Hg
• Oxidation to disulfides