Chapter 4 Alcohols and Alkyl Halides

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Chapter 4Alcohols and Alkyl Halides
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Overview of Chapter
This chapter introduces chemical reactions and
their mechanisms by focusing on two
reactionsthat yield alkyl halides.

• (1) alcohol hydrogen halide
• ROH HX Æ RX H2O
• (2) alkane halogen
• RH X2 Æ RX HX
• Both are substitution reactions

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4.1IUPAC Nomenclatureof Alkyl Halides
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IUPAC Nomenclature
There are several kinds of IUPAC nomenclature.

• The two that are most widely used
  are functional class nomenclature substitutive
  nomenclature
• Both types can be applied to alcohols andalkyl
  halides.

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Functional Class Nomenclature of Alkyl Halides

• Name the alkyl group and the halogen asseparate
  words (alkyl halide)

CH3F
CH3CH2CH2CH2CH2Cl
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Functional Class Nomenclature of Alkyl Halides

• Name the alkyl group and the halogen asseparate
  words (alkyl halide)

CH3F
CH3CH2CH2CH2CH2Cl
Methyl fluoride
Pentyl chloride
1-Ethylhexyl bromide
Cyclohexyl iodide
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Substitutive Nomenclature of Alkyl Halides

• Name as halo-substituted alkanes.
• Number the longest chain containing thehalogen
  in the direction that gives the lowestnumber to
  the substituted carbon.

CH3CH2CH2CH2CH2F
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Substitutive Nomenclature of Alkyl Halides

• Name as halo-substituted alkanes.
• Number the longest chain containing thehalogen
  in the direction that gives the lowestnumber to
  the substituted carbon.

CH3CH2CH2CH2CH2F
1-Fluoropentane
2-Bromopentane
3-Iodopentane
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Substitutive Nomenclature of Alkyl Halides

• Halogen and alkyl groupsare of equal rank when
  it comes to numberingthe chain.
• Number the chain in thedirection that gives the
  lowest number to thegroup (halogen or
  alkyl)that appears first.

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Substitutive Nomenclature of Alkyl Halides
5-Chloro-2-methylheptane
2-Chloro-5-methylheptane
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4.2IUPAC Nomenclatureof Alcohols
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Functional Class Nomenclature of Alcohols

• Name the alkyl group and add "alcohol" as
  aseparate word.

CH3CH2OH
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Functional Class Nomenclature of Alcohols

• Name the alkyl group and add "alcohol" as
  aseparate word.

CH3CH2OH
Ethyl alcohol
1,1-Dimethylbutylalcohol
1-Methylpentyl alcohol
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Substitutive Nomenclature of Alcohols

• Name as "alkanols." Replace -e ending of
  alkanename by -ol.
• Number chain in direction that gives lowest
  numberto the carbon that bears the OH group.

CH3CH2OH
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Substitutive Nomenclature of Alcohols

• Name as "alkanols." Replace -e ending of
  alkanename by -ol.
• Number chain in direction that gives lowest
  numberto the carbon that bears the OH group.

CH3CH2OH
Ethanol
2-Methyl-2-pentanol
2-Hexanol
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Substitutive Nomenclature of Alcohols

• Hydroxyl groups outrank alkyl groups when it
  comes to numberingthe chain.
• Number the chain in thedirection that gives the
  lowest number to thecarbon that bears theOH
  group

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Substitutive Nomenclature of Alcohols
6-Methyl-3-heptanol
5-Methyl-2-heptanol
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4.3Classes of Alcoholsand Alkyl Halides
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Classification

• Alcohols and alkyl halides are classified
  as primary secondary tertiaryaccording to
  their "degree of substitution."
• Degree of substitution is determined by
  countingthe number of carbon atoms directly
  attached tothe carbon that bears the halogen or
  hydroxyl group.

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Classification
H
CH3CH2CH2CH2CH2F
OH
primary alkyl halide
secondary alcohol
secondary alkyl halide
tertiary alcohol