636
Table 6 2:
Carbon-Halogen (C—X) Bond Lengths, Bond
Enthalpies and Dipole Moments
      The preparation of alkyl chloride is carried out either by passing
dry hydrogen chloride gas through a solution of alcohol or by heating
a mixture of alcohol and concentrated aqueous halogen acid The above methods are not applicable for the preparation of aryl
halides because the carbon-oxygen bond in phenols has a partial double
bond character and is difficult to break being stronger than a single
bond (I) From alkanes by free radical halogenation
Free radical chlorination or bromination of alkanes gives a complex
mixture of isomeric mono- and polyhaloalkanes, which is difficult to
The hydroxyl group of an alcohol is replaced by halogen on reaction with
concentrated halogen acids, phosphorus halides or thionyl chloride