Halogenation by reaction at a functional groups
Classifying organic reactions by type highlights similarities between reactions that may at first appear different, and makes learning reaction chemistry easier. The reaction of an alkane with halogen to form a haloalkane is an example of a substitution reaction at saturated carbon.
substitution:
CH3–CH2–H + Cl–Cl
The reaction of an alkane with an elemental halogen to form a haloalkane is unusual as reaction can, in principle occur at any carbon.The most useful preparations of haloalkanes are those that result in introduction of halogen at specific carbon atoms with no change at other carbons. One example is the addition reaction given below.
addition:
CH2=CH2 + Br–Br
Alkenes/alkynes react by addition with with halogen (X2) or HX in the absence of light at the multiply bonded carbons.
substitution:
CH3–CH2–H + Cl–Cl
CH3CH2–Cl + H–Cl
The reaction of an alkane with an elemental halogen to form a haloalkane is unusual as reaction can, in principle occur at any carbon.The most useful preparations of haloalkanes are those that result in introduction of halogen at specific carbon atoms with no change at other carbons. One example is the addition reaction given below.
addition:
CH2=CH2 + Br–Br
Br–CH2–CH2–Br
Alkenes/alkynes react by addition with with halogen (X2) or HX in the absence of light at the multiply bonded carbons.