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Organic Chemistry 4e Carey | |
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Chapter 15: Alcohols, Diols and Thiols
Diols |
Preparing Diols |
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Diols
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Chapter 15:
Alcohols, Diols and Thiols
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Nomenclature:
Diols are named systematically as poly-alcohols, e.g. HOCH2CH2OH
= 1,2-ethanediol, so the same nomenclature rules as for alcohols apply.
1,2-diols are often referred to as vicinal diols.
Functional group suffix = -diol (review)
Functional group prefix = dihydroxy-
Question:
In cis-1,2-cyclohexanediol are the hydroxy groups axial or equatorial ? 
Physical
Properties:
- The polar nature of
the O-H bond (due to the electronegativity difference of the atoms )
results in the formation of hydrogen bonds with other alcohol molecules or
other H-bonding systems (e.g. water). The implications of this are:
- high melting and boiling
points compared to analogous alkanes
- high solubility in
aqueous media
Structure:
- Basically the same as
for alcohols
- Each alcohol functional
group consists of an O atom bonded to a C atom and a H atom via s
bonds.
- Both the C-O
and the O-H bonds are polar due to the high electronegativity of the
O atom.
Reactivity:
- In general the chemistry
of diols is much the same as that of alcohols.