Chapter 24 Phenols

1
Chapter 24Phenols
2
24.1Nomenclature
3
Nomenclature
5-Chloro-2-methylphenol

• named on basis of phenol as parent
• substituents listed in alphabetical order
• lowest numerical sequence first point
  ofdifference rule

4
Nomenclature
1,2-Benzenediol
1,3-Benzenediol
1,4-Benzenediol
(common namepyrocatechol)
(common nameresorcinol)
(common namehydroquinone)
5
Nomenclature
p-Hydroxybenzoic acid

• name on basis of benzoic acid as parent
• higher oxidation states of carbon
  outrankhydroxyl group

6
24.2Structure and Bonding
7
Structure of Phenol

• phenol is planar
• CO bond distance is 136 pm, which isslightly
  shorter than that of CH3OH (142 pm)

8
24.3Physical Properties
The OH group of phenols allows hydrogen
bondingto other phenol molecules and to water.
9
Hydrogen Bonding in Phenols
10
Physical Properties (Table 24.1)
Compared to compounds of similar size
andmolecular weight, hydrogen bonding in phenol
raises its melting point, boiling point,
andsolubility in water.
11
Physical Properties (Table 24.1)
C6H5CH3
C6H5OH
C6H5F
Molecular weight
92
94
96
95
43
41
Melting point (C)
Boilingpoint (C,1 atm)
111
132
85
Solubility inH2O (g/100 mL,25C)
0.05
8.2
0.2